Move main_ios.mm over to public APIs (#2637)

After this patch, main_ios.mm now consumes Flutter.framework via public APIs.
This patch prepares us to move Flutter on iOS over to consuming
Flutter.framework as a binary artifact.

sky/shell/BUILD.gn

@@ -249,14 +249,14 @@ if (is_android) {
     source_set(target_name) {
 
       sources = [
-        "platform/ios/FlutterAppDelegate.h",
-        "platform/ios/FlutterAppDelegate.mm",
         "platform/ios/framework/Headers/Flutter.h",
+        "platform/ios/framework/Headers/FlutterAppDelegate.h",
         "platform/ios/framework/Headers/FlutterDartProject.h",
         "platform/ios/framework/Headers/FlutterMacros.h",
         "platform/ios/framework/Headers/FlutterViewController.h",
         "platform/ios/framework/Source/accessibility_bridge.h",
         "platform/ios/framework/Source/accessibility_bridge.mm",
+        "platform/ios/framework/Source/FlutterAppDelegate.mm",
         "platform/ios/framework/Source/FlutterDartProject.mm",
         "platform/ios/framework/Source/FlutterDartProject_Internal.h",
         "platform/ios/framework/Source/FlutterDartSource.h",
@@ -378,6 +378,7 @@ if (is_android) {
     copy("framework_headers") {
       sources = [
         "platform/ios/framework/Headers/Flutter.h",
+        "platform/ios/framework/Headers/FlutterAppDelegate.h",
         "platform/ios/framework/Headers/FlutterDartProject.h",
         "platform/ios/framework/Headers/FlutterMacros.h",
         "platform/ios/framework/Headers/FlutterViewController.h",

sky/shell/platform/ios/FlutterAppDelegate.h → sky/shell/platform/ios/framework/Headers/FlutterAppDelegate.h

-// Copyright 2015 The Chromium Authors. All rights reserved.
+// Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#ifndef FLUTTER_FLUTTERAPPDELEGATE_H_
+#define FLUTTER_FLUTTERAPPDELEGATE_H_
+
 #import <UIKit/UIKit.h>
 
+#include "FlutterMacros.h"
+
+// A simple app delegate that creates a single full-screen Flutter application.
+// Using FlutterAppDelegate is optional. The framework provides this interface
+// to make it easy to get started with simple Flutter apps.
+FLUTTER_EXPORT
 @interface FlutterAppDelegate : UIResponder<UIApplicationDelegate>
 
 @property(strong, nonatomic) UIWindow* window;
 
 @end
+
+#endif  // FLUTTER_FLUTTERDARTPROJECT_H_

sky/shell/platform/ios/framework/Headers/FlutterDartProject.h

@@ -20,6 +20,8 @@ FLUTTER_EXPORT
                           packages:(NSURL*)dartPackages
     NS_DESIGNATED_INITIALIZER;
 
+- (instancetype)initFromDefaultSourceForConfiguration;
+
 @end
 
 #endif  // FLUTTER_FLUTTERDARTPROJECT_H_

sky/shell/platform/ios/framework/Headers/FlutterViewController.h

@@ -20,4 +20,7 @@ FLUTTER_EXPORT
 
 @end
 
+// Initializes Flutter for this process. Need only be called once per process.
+FLUTTER_EXPORT void FlutterInit(int argc, const char* argv[]);
+
 #endif  // FLUTTER_FLUTTERVIEWCONTROLLER_H_

sky/shell/platform/ios/FlutterAppDelegate.mm → sky/shell/platform/ios/framework/Source/FlutterAppDelegate.mm

@@ -2,46 +2,16 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "base/command_line.h"
-#include "base/trace_event/trace_event.h"
-#include "sky/shell/platform/ios/FlutterAppDelegate.h"
+#include "sky/shell/platform/ios/framework/Headers/FlutterAppDelegate.h"
 #include "sky/shell/platform/ios/framework/Headers/FlutterViewController.h"
-#include "sky/shell/switches.h"
-
-NSURL* URLForSwitch(const char* name) {
-  auto cmd = *base::CommandLine::ForCurrentProcess();
-  NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
-
-  if (cmd.HasSwitch(name)) {
-    auto url = [NSURL fileURLWithPath:@(cmd.GetSwitchValueASCII(name).c_str())];
-    [defaults setURL:url forKey:@(name)];
-    [defaults synchronize];
-    return url;
-  }
-
-  return [defaults URLForKey:@(name)];
-}
 
 @implementation FlutterAppDelegate
 
 - (BOOL)application:(UIApplication*)application
     didFinishLaunchingWithOptions:(NSDictionary*)launchOptions {
-  TRACE_EVENT0("flutter", "applicationDidFinishLaunchingWithOptions");
 
-#if TARGET_IPHONE_SIMULATOR
-  FlutterDartProject* project = [[FlutterDartProject alloc]
-      initWithFLXArchive:URLForSwitch(sky::shell::switches::kFLX)
-                dartMain:URLForSwitch(sky::shell::switches::kMainDartFile)
-                packages:URLForSwitch(sky::shell::switches::kPackages)];
-#else
-  NSString* bundlePath =
-      [[NSBundle mainBundle] pathForResource:@"FlutterApplication"
-                                      ofType:@"framework"
-                                 inDirectory:@"Frameworks"];
-  NSBundle* bundle = [NSBundle bundleWithPath:bundlePath];
   FlutterDartProject* project =
-      [[FlutterDartProject alloc] initWithPrecompiledDartBundle:bundle];
-#endif
+      [[FlutterDartProject alloc] initFromDefaultSourceForConfiguration];
 
   CGRect frame = [UIScreen mainScreen].bounds;
   UIWindow* window = [[UIWindow alloc] initWithFrame:frame];
@@ -76,7 +46,7 @@ NSURL* URLForSwitch(const char* name) {
   [[NSNotificationCenter defaultCenter] postNotificationName:@"openURL"
                                                       object:self
                                                     userInfo:dict];
-  BOOL handled = ((NSNumber *)dict[@"handled"][@"value"]).boolValue;
-  return handled;
+  return ((NSNumber *)dict[@"handled"][@"value"]).boolValue;
 }
+
 @end

sky/shell/platform/ios/framework/Source/FlutterDartProject.mm

@@ -3,7 +3,32 @@
 // found in the LICENSE file.
 
 #include "sky/shell/platform/ios/framework/Source/FlutterDartProject_Internal.h"
+
+#include "base/command_line.h"
 #include "sky/shell/platform/ios/framework/Source/FlutterDartSource.h"
+#include "sky/shell/switches.h"
+
+namespace {
+
+#if TARGET_IPHONE_SIMULATOR
+
+NSURL* URLForSwitch(const char* name) {
+  auto cmd = *base::CommandLine::ForCurrentProcess();
+  NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
+
+  if (cmd.HasSwitch(name)) {
+    auto url = [NSURL fileURLWithPath:@(cmd.GetSwitchValueASCII(name).c_str())];
+    [defaults setURL:url forKey:@(name)];
+    [defaults synchronize];
+    return url;
+  }
+
+  return [defaults URLForKey:@(name)];
+}
+
+#endif  // TARGET_IPHONE_SIMULATOR
+
+}  // namespace
 
 @implementation FlutterDartProject {
   NSBundle* _precompiledDartBundle;
@@ -48,6 +73,24 @@
   return self;
 }
 
+#pragma mark - Convenience initializers
+
+- (instancetype)initFromDefaultSourceForConfiguration {
+  #if TARGET_IPHONE_SIMULATOR
+    return [self
+        initWithFLXArchive:URLForSwitch(sky::shell::switches::kFLX)
+                  dartMain:URLForSwitch(sky::shell::switches::kMainDartFile)
+                  packages:URLForSwitch(sky::shell::switches::kPackages)];
+  #else
+    NSString* bundlePath =
+        [[NSBundle mainBundle] pathForResource:@"FlutterApplication"
+                                        ofType:@"framework"
+                                   inDirectory:@"Frameworks"];
+    NSBundle* bundle = [NSBundle bundleWithPath:bundlePath];
+    return [self initWithPrecompiledDartBundle:bundle];
+  #endif
+}
+
 #pragma mark - Common initialization tasks
 
 - (void)checkReadiness {

sky/shell/platform/ios/framework/Source/FlutterViewController.mm

@@ -23,6 +23,12 @@
 #include "sky/shell/shell.h"
 #include "sky/shell/shell_view.h"
 
+void FlutterInit(int argc, const char* argv[]) {
+  NSBundle* bundle = [NSBundle bundleForClass:[FlutterViewController class]];
+  NSString* icuDataPath = [bundle pathForResource:@"icudtl" ofType:@"dat"];
+  sky::shell::PlatformMacMain(argc, argv, icuDataPath.UTF8String);
+}
+
 @implementation FlutterViewController {
   FlutterDartProject* _dartProject;
   UIInterfaceOrientationMask _orientationPreferences;
@@ -63,17 +69,10 @@
 #pragma mark - Common view controller initialization tasks
 
 - (void)performCommonViewControllerInitialization {
-  if (_initialized) {
+  if (_initialized)
     return;
-  }
-
   _initialized = YES;
 
-  NSBundle* bundle = [NSBundle bundleForClass:[self class]];
-  NSString* icuDataPath = [bundle pathForResource:@"icudtl" ofType:@"dat"];
-
-  sky::shell::PlatformMacMain(0, nullptr, icuDataPath.UTF8String);
-
   _orientationPreferences = UIInterfaceOrientationMaskAll;
   _dynamicServiceLoader = [[FlutterDynamicServiceLoader alloc] init];
   _viewportMetrics = sky::ViewportMetrics::New();

sky/shell/platform/ios/main_ios.mm

-// Copyright 2015 The Chromium Authors. All rights reserved.
+// Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import <UIKit/UIKit.h>
 
-#include "sky/shell/platform/ios/FlutterAppDelegate.h"
-#include "sky/shell/platform/mac/platform_mac.h"
+#include "sky/shell/platform/ios/framework/Headers/FlutterAppDelegate.h"
+#include "sky/shell/platform/ios/framework/Headers/FlutterViewController.h"
 
 int main(int argc, const char* argv[]) {
-  // iOS does use the FlutterViewController that initializes the platform but
-  // we have the command line args here. So call it now.
-  sky::shell::PlatformMacMain(argc, argv, "");
+  FlutterInit(argc, argv);
   return UIApplicationMain(argc, (char**)argv, nil,
                            NSStringFromClass([FlutterAppDelegate class]));
 }