Bug 1320587 - Force first paint when (re-)attaching Gecko to Java. r=jchen

MozReview-Commit-ID: 6vUbIXTPNLQ

--HG--
extra : rebase_source : 24d6e8f5502568443f35c59963a66d8fe8ac4056

widget/android/nsWindow.cpp

@@ -1067,14 +1067,7 @@ public:
             return; // Already shut down.
         }
 
-        const auto& layerClient = GeckoLayerClient::Ref::From(aClient);
-
-        // If resetting is true, Android destroyed our GeckoApp activity and we
-        // had to recreate it, but all the Gecko-side things were not
-        // destroyed.  We therefore need to link up the new java objects to
-        // Gecko, and that's what we do here.
-        const bool resetting = !!mLayerClient;
-        mLayerClient = layerClient;
+        mLayerClient = GeckoLayerClient::Ref::From(aClient);
 
         MOZ_ASSERT(aNPZC);
         auto npzc = NativePanZoomController::LocalRef(
@@ -1082,15 +1075,12 @@ public:
                 NativePanZoomController::Ref::From(aNPZC));
         mWindow->mNPZCSupport.Attach(npzc, mWindow, npzc);
 
-        layerClient->OnGeckoReady();
+        mLayerClient->OnGeckoReady();
 
-        if (resetting) {
-            // Since we are re-linking the new java objects to Gecko, we need
-            // to get the viewport from the compositor (since the Java copy was
-            // thrown away) and we do that by setting the first-paint flag.
-            if (RefPtr<CompositorBridgeParent> bridge = mWindow->GetCompositorBridgeParent()) {
-                bridge->ForceIsFirstPaint();
-            }
+        // Set the first-paint flag so that we (re-)link any new Java objects
+        // to Gecko, co-ordinate viewports, etc.
+        if (RefPtr<CompositorBridgeParent> bridge = mWindow->GetCompositorBridgeParent()) {
+            bridge->ForceIsFirstPaint();
         }
     }