A customer trace on recent 15.3 release shows that `Microsoft.CodeAnalysis.CSharp!Binder.IsAccessibleHelper` is taking up large amount of CPU stacks for LookupSymbols(name) calls from IDE analyzers. This change optimizes the performance of this code path by adding a name check before doing accessibilty checks.

merge dev15.3.x to dev15.4.x

removed ImmutableArray from json.net usage. and moved to IList

Merge dev15.3.x to dev15.4.x

Be resilient to the document being shorter than when it started when we get a completoin item description.

Don't crash in QuickInfo if the search for linked tokens goes out of bounds

Works around 3/4 of the dumps investigated for
https://devdiv.visualstudio.com/DevDiv/_workitems?id=209299

Be resilient to the document being shorter than when it started when we get a completoin item description.

Merge dev15.3.x to dev15.4.x

Merge remote-tracking branch 'upstream/dev15.3.x' into merges/dev15.3.x-to-dev15.4.x-20170816-070009

Ensure dev15.4.x has the correct contents for inserting

Fixes https://devdiv.visualstudio.com/DevDiv/_workitems?id=479492

Fix ctrl click crash

Fixes https://devdiv.visualstudio.com/DevDiv/_workitems?id=479492

This reverts commit da18ba34, reversing
changes made to f5e5a556.

This reverts commit b76c7b4e, reversing
changes made to a526dba8.

This reverts commit ad828aad, reversing
changes made to 5d82127f.

Add null checks for TaskExtensions before deferred execution

Fix options page

No More Non-Fatal Watsons After OOM

A null value for certain arguments in TaskExtensions results in an exception.
We want this exception to reveal the caller who passed a null value. This
commit updates methods which defer the evaluation of the argument to explicitly
check for null early so the caller is revealed in the stack trace.

CSharpLanguageInstructionDecoder implementation of IDkmLanguageInstructionDecoder is slow (#20834) (#21315)

removed semantic version tracking code which recently caused some iss…

removed semantic version tracking code which recently caused some issue on RPS test. this code is already removed from master (15.5)

Once we've seen and "handled" an OutOfMemoryException we're very likely to see
more, and likely to see other kinds of exceptions that are a direct result of
the OOM. We don't want to report these as they aren't helpful and obscure
other, unrelated issues when analyzing reports.

Here we stop reporting all non-fatal errors after the first OOM.

The `Report(string, Exception)` and `Report(string, Exception, Func<IFaultUtility, int>)`
methods were almost identical. The former now calls the latter and passes in a default
implementation of `Func<IFaultUtility, int>`.

Implement INavigableSymbols

Implement ISuggestedActionsSource2