Cherry-pick: [Android WebView] API to enable fullscreen.

NOTE: this cherry-pick will only be landed after these changes
https://googleplex-android-review.git.corp.google.com/#/c/523937/
https://googleplex-android-review.git.corp.google.com/#/c/523939/

Added a new method, ie. AwContents.setFullscreenSupported, that
will be called by the glue layer when the WebView app supports
fullscreen.

This is follow-up change to:
https://codereview.chromium.org/428633004/

BUG=389496

Review URL: https://codereview.chromium.org/425343002

Cr-Commit-Position: refs/heads/master@{#288723}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@288723 0039d316-1c4b-4281-b951-d872f2087c98

Conflicts:
	android_webview/javatests/src/org/chromium/android_webview/test/AwContentsClientFullScreenVideoTest.java
	android_webview/native/aw_settings.cc
	content/public/common/common_param_traits_macros.h
	content/public/common/web_preferences.cc
	content/public/common/web_preferences.h
	content/renderer/render_view_impl.cc

Change-Id: Ie0fb7da4a7ccb5557a22ba5c2ab1d9df2e373876
10 files changed