Fix Flash fullscreen focus regressions, and add interactive_ui_tests.

This revisits focus handling logic relating to Flash fullscreen in
WebContentsImpl.  Before this change, calls to WebContentsImpl::Focus()
would directly call RenderWidgetHostView::Focus(), but this prevented
WebContentsView and its delegate from "shadowing" these focus changes in
the browser UI.  In other words, on Windows/Linux/CrOS, the focus state
for widgets in the ui::views toolkit were not necessarily synchronized
with the render widget's focus state (see bug for details).

90% of this change adds regression testing for everything described
above.  The tests run a simulated fullscreened Flash widget, and then
invoke user keyboard and mouse actions on the browser UI to confirm both
the Flash widget and ui::views are in agreement and respond correctly to
focus changes; also, including focus store/restore when switching tabs.

BUG=403641
TEST=Repro steps in bug 403641; and also that focus remains with the omnibox or tab contents when switching back and forth to other tabs.  New automated interactive_ui_tests.

Review URL: https://codereview.chromium.org/670653005

Cr-Commit-Position: refs/heads/master@{#301269}

1 files changed, 1 insertions, 0 deletions

diff --git a/content/browser/web_contents/web_contents_impl.h b/content/browser/web_contents/web_contents_impl.h
index 60fdc72..c437796 100644
--- a/content/browser/web_contents/web_contents_impl.h
+++ b/content/browser/web_contents/web_contents_impl.h
@@ -515,6 +515,7 @@ class CONTENT_EXPORT WebContentsImpl
   // RenderWidgetHostDelegate --------------------------------------------------
 
   void RenderWidgetDeleted(RenderWidgetHostImpl* render_widget_host) override;
+  void RenderWidgetGotFocus(RenderWidgetHostImpl* render_widget_host) override;
   bool PreHandleKeyboardEvent(const NativeWebKeyboardEvent& event,
                               bool* is_keyboard_shortcut) override;
   void HandleKeyboardEvent(const NativeWebKeyboardEvent& event) override;