linux_aura: Reenable PPAPI tests.

BUG=318961

Review URL: https://codereview.chromium.org/72103002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235598 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 235598
Add chrome_strings dependency to app_shim.gypi

BUG=317699

Review URL: https://codereview.chromium.org/72273004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235599 0039d316-1c4b-4281-b951-d872f2087c98
winaura: Do not create WindowObservers for BrowserPlugin.

WindowObserver is not necessary for BrowserPlugin.
Moreover, if BrowserPlugin navigates to an Interstitial page,
tearing down its embedder causes a crash b/c it tries
to cast the Interstitial's WC's view to WCViewAura, which
actually is a WCViewGuest. The ToRenderWidgetHostViewAura does
not work in this scenario because the RWH's process points to
Interstitial's RenderProcess, whose IsGuest() is false. The
simpler fix hence is to get rid of WindowObserver for
BrowserPlugin.

This will also fix a flaky test on windows:
WebViewTest.InterstitialTeardown.


BUG=316298,297014
Test=On Windows Aura, load an app with a <webview> pointing
to a page that shows an interstitial, e.g. try navigating
to https://test.com. After the interstitial is visible, close
the app. The fix would make the browser not crash.

Review URL: https://codereview.chromium.org/72283002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235600 0039d316-1c4b-4281-b951-d872f2087c98
Limit number of extensions and mime types an app can have handlers for.

This limit matches that applied by the web store to prevent surprises when uploading apps.

This change also adds manifest tests for file_handlers, which were absent.

BUG=315210

Review URL: https://codereview.chromium.org/72343003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235601 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 235601
[SyncFS] Implement MetadataDatabase::LowerTrackerPriority

 * Add low_priority_dirty_tracker_ to MetadataDatabase for
   MetadataDatabase::LowerTrackerPriority and change other parts of
   MetadataDatabase to be consistent to it.

R=kinuko@chromium.org, nhiroki@chromium.org, kinuko, nhiroki
BUG=240165

Review URL: https://codereview.chromium.org/72353002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235602 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 235602