Bug 215220 Unable to receive caret-move event in HTML document

r=aaron, sr=henry.jia
Bug 217311 [ATK Accessibility] wrong text structure for HTML text
r=bolian.yin (Not in the default build)
Bug 218992 no placeholder for broken image
r=bolian.yin (Not in the default build)
This patch aims at solving some ATK accessible text issues. The main parts of this patch (inside accessibility/src/atk directory or the #ifdef MOZ_ACCESSIBILITY_ATK/#endif macro) are not in the default build (it gets built only when the default toolkit set to gtk2)

layout/html/base/src/nsTextFrame.cpp

@@ -807,7 +807,6 @@ protected:
 #ifdef ACCESSIBILITY
 NS_IMETHODIMP nsTextFrame::GetAccessible(nsIAccessible** aAccessible)
 {
-#ifndef MOZ_ACCESSIBILITY_ATK
   if (mRect.width > 0 || mRect.height > 0) {
 
     nsCOMPtr<nsIAccessibilityService> accService = do_GetService("@mozilla.org/accessibilityService;1");
@@ -816,7 +815,6 @@ NS_IMETHODIMP nsTextFrame::GetAccessible(nsIAccessible** aAccessible)
       return accService->CreateHTMLTextAccessible(NS_STATIC_CAST(nsIFrame*, this), aAccessible);
     }
   }
-#endif
   return NS_ERROR_FAILURE;
 }
 #endif