DevTools: Fix Inspect Element action for OOP iframes.

RenderViewContextMenu has recently become aware of the frame it is being called for. This makes it possible direct the InspectElement message to the correct renderer which is necessary of the "Inspect Element" action to work correctly with OOP iframes.

This automatically works correctly for BrowserPlugin as well, so WebContents::GetRenderViewHostAtPosition and all supporting code across can be removed now.

BUG=345700

Review URL: https://codereview.chromium.org/187673004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255672 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 255672
IndexedDB: Don't timeout read-only transactions

Chrome introduced a transaction timeout to deal with potentially wedged
renderers (e.g. JS execution halted, etc) failing to complete transactions,
leaving the browser's transaction queue in a bad state. This was done
for all transactions, but since read-only transactions don't hold up
the queue it's safe to ignore them, which can reduce false-positives.

BUG=339229

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=254846

Review URL: https://codereview.chromium.org/180163010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255673 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 255673