Fix <webview>.contextMenus requiring chrome.contextMenus permission.

webview.json and webview_custom_bindings.js had reference directly to
context_menus.json (chrome.contextMenus). This CL moves the common
part under contextMenusInternal and makes webview and
chrome.contextMenus use that instead.

BUG=140315
Test=<webview> using contextMenus API shouldn't require to
specify {"permissions": "contextMenus"}.

Review URL: https://codereview.chromium.org/190393002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256494 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 256494
[Metrics] Don't require clients of StatisticsDeltaReader to call StatisticsRecorder::Initialize().

BUG=none
TEST=none
R=asvitkine@chromium.org
TBR=willchan@chromium.org

Review URL: https://codereview.chromium.org/184203002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256495 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 256495