[Android] Eliminate JNI hop for critical path gestures

Previously, all gestures would pass through Java as they were filtered prior
to being forwarded to the renderer.  However, only a small subset of gestures
really need to be seen during this filtering phase.  The rest can be accommodated
simply by inspecting the corresponding gesture ack.  This saves ~20us per
GestureScrollUpdate and GesturePinchUpdate.

BUG=341613

Review URL: https://codereview.chromium.org/164643002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251181 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 251181
Add PPB_ContentDecryptor_Private;0.11 to histograms.xml.

BUG=338831

Review URL: https://codereview.chromium.org/163603005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251182 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 251182