AutoFill: Release the cached frame when we receive the frameDestroyed() message
from WebKit.

BUG=48857
TEST=none

Review URL: http://codereview.chromium.org/3173005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@55789 0039d316-1c4b-4281-b951-d872f2087c98
void RenderView::OnCopyToFindPboard() {
  if (!webview())
    return;

  WebFrame* frame = webview()->focusedFrame();
  if (frame->hasSelection()) {
    string16 selection = frame->selectionAsText();
    RenderThread::current()->Send(
        new ViewHostMsg_ClipboardFindPboardWriteStringAsync(selection));
  }

  UserMetricsRecordAction("CopyToFindPboard");
}

void RenderView::OnCopyToFindPboard() {
  if (!webview())
    return;

  WebFrame* frame = webview()->focusedFrame();
  if (frame->hasSelection()) {
    string16 selection = frame->selectionAsText();
    RenderThread::current()->Send(
        new ViewHostMsg_ClipboardFindPboardWriteStringAsync(selection));
  }

  UserMetricsRecordAction("CopyToFindPboard");
}
