Fix race condition in Paint.hasGlyph()

The caller of FontFamily::hasVariationSelector needs to acquire the
lock before calling it, but FontCollection::hasVariationSelector
didn't acquire the lock. This caused a race condition.
This CL fixes this race condition.

Also, it turned out that assertMinikinLocked didn't assert even on
eng or userdebug device. This CL enables assertion on eng and userdebug
device since this assertion must be treated as bug.

BUG: 26323806

Change-Id: I9c4b1e1f09c6793e387fbdb8bb654cc0a13c65d5

libs/minikin/Android.mk

@@ -47,11 +47,18 @@ minikin_shared_libraries := \
     libicuuc \
     libutils
 
+ifneq (,$(filter userdebug eng, $(TARGET_BUILD_VARIANT)))
+# Enable race detection on eng and userdebug build.
+enable_race_detection := -DENABLE_RACE_DETECTION
+else
+enable_race_detection :=
+endif
+
 LOCAL_MODULE := libminikin
 LOCAL_EXPORT_C_INCLUDE_DIRS := frameworks/minikin/include
 LOCAL_SRC_FILES := $(minikin_src_files)
 LOCAL_C_INCLUDES := $(minikin_c_includes)
-LOCAL_CPPFLAGS += -Werror -Wall -Wextra
+LOCAL_CPPFLAGS += -Werror -Wall -Wextra $(enable_race_detection)
 LOCAL_SHARED_LIBRARIES := $(minikin_shared_libraries)
 
 include $(BUILD_SHARED_LIBRARY)
@@ -63,7 +70,7 @@ LOCAL_MODULE_TAGS := optional
 LOCAL_EXPORT_C_INCLUDE_DIRS := frameworks/minikin/include
 LOCAL_SRC_FILES := $(minikin_src_files)
 LOCAL_C_INCLUDES := $(minikin_c_includes)
-LOCAL_CPPFLAGS += -Werror -Wall -Wextra
+LOCAL_CPPFLAGS += -Werror -Wall -Wextra $(enable_race_detection)
 LOCAL_SHARED_LIBRARIES := $(minikin_shared_libraries)
 
 include $(BUILD_STATIC_LIBRARY)
@@ -76,7 +83,7 @@ LOCAL_MODULE := libminikin_host
 LOCAL_MODULE_TAGS := optional
 LOCAL_EXPORT_C_INCLUDE_DIRS := frameworks/minikin/include
 LOCAL_C_INCLUDES := $(minikin_c_includes)
-LOCAL_CPPFLAGS += -Werror -Wall -Wextra
+LOCAL_CPPFLAGS += -Werror -Wall -Wextra $(enable_race_detection)
 LOCAL_SHARED_LIBRARIES := liblog libicuuc-host
 
 LOCAL_SRC_FILES := Hyphenator.cpp

libs/minikin/FontCollection.cpp

@@ -223,6 +223,7 @@ bool FontCollection::hasVariationSelector(uint32_t baseCodepoint,
     // Currently mRanges can not be used here since it isn't aware of the variation sequence.
     // TODO: Use mRanges for narrowing down the search range.
     for (size_t i = 0; i < mFamilies.size(); i++) {
+        AutoMutex _l(gMinikinLock);
         if (mFamilies[i]->hasVariationSelector(baseCodepoint, variationSelector)) {
           return true;
         }

libs/minikin/MinikinInternal.cpp

@@ -25,7 +25,9 @@ namespace android {
 Mutex gMinikinLock;
 
 void assertMinikinLocked() {
-    LOG_FATAL_IF(gMinikinLock.tryLock() == 0);
+#ifdef ENABLE_RACE_DETECTION
+    LOG_ALWAYS_FATAL_IF(gMinikinLock.tryLock() == 0);
+#endif
 }
 
 }