Sync requestFullscreen() and exitFullscreen() algorithms with the spec

third_party/WebKit/Source/web/FullscreenController.cpp

Index: third_party/WebKit/Source/web/FullscreenController.cpp
diff --git a/third_party/WebKit/Source/web/FullscreenController.cpp b/third_party/WebKit/Source/web/FullscreenController.cpp
index 4099914d4cc5d3efcc3efca0d683062cd25b36d1..bc592d27f0e00ab04bc54a074dbd36fb46d3addd 100644
--- a/third_party/WebKit/Source/web/FullscreenController.cpp
+++ b/third_party/WebKit/Source/web/FullscreenController.cpp
@@ -88,6 +88,9 @@ void FullscreenController::didEnterFullscreen() {
         fullscreen->didEnterFullscreen();
     }
   }
+
+  // TODO(foolip): If the top level browsing context (main frame) ends up with
+  // no fullscreen element, exit fullscreen again to recover.
 }
 
 void FullscreenController::didExitFullscreen() {
@@ -100,33 +103,32 @@ void FullscreenController::didExitFullscreen() {
 
   updatePageScaleConstraints(true);
 
-  // Set |m_state| so that any |exitFullscreen()| calls from within
-  // |Fullscreen::didExitFullscreen()| do not call
-  // |WebFrameClient::exitFullscreen()| again.
-  // TODO(foolip): Remove this when state changes and events are synchronized
-  // with animation frames. https://crbug.com/402376
-  m_state = State::ExitingFullscreen;
+  // We need to wait until style and layout are updated in order to properly
+  // restore scroll offsets since content may not be overflowing in the same way
+  // until they are.
+  m_state = State::NeedsScrollAndScaleRestore;
 
-  // Notify all local frames that we have exited fullscreen.
-  // TODO(foolip): This should only need to notify the topmost local roots. That
-  // doesn't currently work because |Fullscreen::m_currentFullScreenElement|
-  // isn't set for the topmost document when an iframe goes fullscreen, but can
-  // be done once |m_currentFullScreenElement| is gone and all state is in the
-  // fullscreen element stack. https://crbug.com/402421
-  for (Frame* frame = m_webViewImpl->page()->mainFrame(); frame;
-       frame = frame->tree().traverseNext()) {
-    if (!frame->isLocalFrame())
+  // Notify the topmost local frames that we have exited fullscreen.
+  // |Fullscreen::didExitFullscreen()| will take care of descendant frames.
+  for (Frame* frame = m_webViewImpl->page()->mainFrame(); frame;) {
+    Frame* nextFrame = frame->tree().traverseNext();
+
+    if (frame->isRemoteFrame()) {
+      frame = nextFrame;
       continue;
+    }
+
+    DCHECK(frame->isLocalRoot());
     if (Document* document = toLocalFrame(frame)->document()) {
       if (Fullscreen* fullscreen = Fullscreen::fromIfExists(*document))
         fullscreen->didExitFullscreen();
     }
-  }
 
-  // We need to wait until style and layout are updated in order to properly
-  // restore scroll offsets since content may not be overflowing in the same way
-  // until they are.
-  m_state = State::NeedsScrollAndScaleRestore;
+    // Skip over all descendant frames.
+    while (nextFrame && nextFrame->tree().isDescendantOf(frame))
+      nextFrame = nextFrame->tree().traverseNext();
+    frame = nextFrame;
+  }
 }
 
 void FullscreenController::enterFullscreen(LocalFrame& frame) {
@@ -183,7 +185,7 @@ void FullscreenController::fullscreenElementChanged(Element* fromElement,
   DCHECK_NE(fromElement, toElement);
 
   if (toElement) {
-    DCHECK(Fullscreen::isCurrentFullScreenElement(*toElement));
+    DCHECK(Fullscreen::isFullscreenElement(*toElement));
 
     if (isHTMLVideoElement(*toElement)) {
       HTMLVideoElement& videoElement = toHTMLVideoElement(*toElement);
@@ -199,7 +201,7 @@ void FullscreenController::fullscreenElementChanged(Element* fromElement,
   }
 
   if (fromElement) {
-    DCHECK(!Fullscreen::isCurrentFullScreenElement(*fromElement));
+    DCHECK(!Fullscreen::isFullscreenElement(*fromElement));
 
     if (isHTMLVideoElement(*fromElement)) {
       // If the video used overlay fullscreen mode, restore the transparency.