Moved the code which sets focus to the dummy activation window created for windowless plugins from the TrackPopupMenu intercept to the PlatformHandleInputEvent function. This ensures that the plugin thread has focus for windowless plugins which don't have the TrackPopupMenu intercept.
Moved the code which sets focus to the dummy activation window created for windowless plugins
from the TrackPopupMenu intercept to the PlatformHandleInputEvent function. This ensures
that the plugin thread has focus for windowless plugins which don't have the TrackPopupMenu
intercept.

The bug which we are trying to fix is flaky behavior of the context menu in windowless plugins
i.e. selections are ignored at times and we cannot scroll through the menu using the keyboard.
This is because these messages are dispatched at times by Chrome's message loop which executes
in the context of the windows modal loop. This is because we allow nested task execution to ensure
that the windowless plugin continues to paint while the context menu is displayed. Chrome's message
loop dispatching input messages starves the TrackPopupMenu loop which expects to handle these
messages leading to the problem.

I also found that we need to allow popups to be displayed in 
the context of input messages in windowless plugins. This is on the same lines as Firefox and Safari. 
I also updated the list of user gesture messages.

A CL providing a facility to the message loop object indicating that an os modal loop is in effect
is also under review.  http://codereview.chromium.org/6676099/

BUG=59864
TEST=manually as described in the bug.

R=jam@chromium.org,darin@chromium.org,*,ananta@chromium.org
Review URL: http://codereview.chromium.org/6696050

git-svn-id: http://src.chromium.org/svn/trunk/src@79302 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 9b9b516ab7551b114a7f32e487792e7e46c0bfde
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser