Add --disable-compositor-touch-hit-testing flag

Plumb the flag to blink and the compositor.
Disable by default in Android webview for now.

Depends on blink CL: https://src.chromium.org/viewvc/blink?view=rev&revision=158956

BUG=303945

Review URL: https://codereview.chromium.org/25904004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@227511 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 319b1927..688ffc9 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -1750,6 +1750,13 @@
     SINGLE_VALUE_TYPE(chromeos::switches::kEnableFirstRunUI)
   },
 #endif
+  {
+    "disable-compositor-touch-hit-testing",
+    IDS_FLAGS_DISABLE_COMPOSITOR_TOUCH_HIT_TESTING_NAME,
+    IDS_FLAGS_DISABLE_COMPOSITOR_TOUCH_HIT_TESTING_DESCRIPTION,
+    kOsAll,
+    SINGLE_VALUE_TYPE(cc::switches::kDisableCompositorTouchHitTesting),
+  },
 };
 
 const Experiment* experiments = kExperiments;