Client-side phishing detection: grab snapshot of custom sized view.

Client-side phishing detection needs to be able to take a snapshot of a
particular page that has a constant size and aspect ratio (e.g., 1024x768).
This CL adds a helper function (safe_browsing::GrabPhishingThumbnail)
which re-sizes the view a given size, grabs the snapshot, and then re-sizes
the view back to its previous size.  Note: this function can be slow since
it might re-layout the page twice.

This function will only be called if we are very confident that the current page
is a phishing site in which case we are OK with taking a slow snapshot.

Also, this CL adds a test for the OnMsgPaintAtSize method in the RenderWidget
since it does something very similar than the new Thumbnailer.

BUG=None
TEST=GrabPhishingThumbnail

Review URL: http://codereview.chromium.org/3380001

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@60368 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 8 insertions, 0 deletions

diff --git a/chrome/renderer/render_view.h b/chrome/renderer/render_view.h
index bf43b2e..f0dad4d4 100644
--- a/chrome/renderer/render_view.h
+++ b/chrome/renderer/render_view.h
@@ -220,6 +220,14 @@ class RenderView : public RenderWidget,
     return page_click_tracker_.get();
   }
 
+  // Returns true if we should display scrollbars for the given view size and
+  // false if the scrollbars should be hidden.
+  bool should_display_scrollbars(int width, int height) const {
+    return (!send_preferred_size_changes_ ||
+            (disable_scrollbars_size_limit_.width() <= width ||
+             disable_scrollbars_size_limit_.height() <= height));
+  }
+
   // Called from JavaScript window.external.AddSearchProvider() to add a
   // keyword for a provider described in the given OpenSearch document.
   void AddSearchProvider(const std::string& url);