Hide overlay play button if it can't be shown without clipping

third_party/WebKit/Source/core/html/shadow/MediaControls.cpp

Index: third_party/WebKit/Source/core/html/shadow/MediaControls.cpp
diff --git a/third_party/WebKit/Source/core/html/shadow/MediaControls.cpp b/third_party/WebKit/Source/core/html/shadow/MediaControls.cpp
index 3d5cff44270ef8cc0f3189a9601eb66169b10e9c..f1412e532ccabe46e398c64534d6f34c2e58772f 100644
--- a/third_party/WebKit/Source/core/html/shadow/MediaControls.cpp
+++ b/third_party/WebKit/Source/core/html/shadow/MediaControls.cpp
@@ -29,6 +29,9 @@
 #include "bindings/core/v8/ExceptionState.h"
 #include "core/dom/ClientRect.h"
 #include "core/dom/Fullscreen.h"
+#include "core/dom/ResizeObserver.h"
+#include "core/dom/ResizeObserverCallback.h"
+#include "core/dom/ResizeObserverEntry.h"
 #include "core/dom/TaskRunnerHelper.h"
 #include "core/events/MouseEvent.h"
 #include "core/frame/Settings.h"
@@ -45,6 +48,18 @@
 
 namespace blink {
 
+namespace {
+constexpr int kOverlayPlayButtonWidth = 48;

[mlamouri (slow - plz ping), 2017/02/27 18:22:58]

style: leave empty line above `constexpr`

[steimel, 2017/02/28 00:59:47]

Done.

+constexpr int kOverlayPlayButtonHeight = 48;
+constexpr int kOverlayBottomMargin = 10;
+constexpr int kAndroidMediaPanelHeight = 48;
+
+constexpr int kMinWidthForOverlayPlayButton = kOverlayPlayButtonWidth;
+constexpr int kMinHeightForOverlayPlayButton = kOverlayPlayButtonHeight +
+                                               (2 * kAndroidMediaPanelHeight) +
+                                               (2 * kOverlayBottomMargin);
+}  // namespace

[mlamouri (slow - plz ping), 2017/02/27 18:22:58]

style: empty line + "anonymous namespace"

[steimel, 2017/02/28 00:59:47]

Done.

+
 // If you change this value, then also update the corresponding value in
 // LayoutTests/media/media-controls.js.
 static const double timeWithoutMouseMovementBeforeHidingMediaControls = 3;
@@ -114,6 +129,33 @@ class MediaControls::BatchedControlUpdate {
 // Count of number open batches for controls visibility.
 int MediaControls::BatchedControlUpdate::s_batchDepth = 0;
 
+class MediaControls::MediaControlsResizeObserverCallback

[mlamouri (slow - plz ping), 2017/02/27 18:22:58]

nit: add `final`

[steimel, 2017/02/28 00:59:46]

Done.

+    : public ResizeObserverCallback {
+ public:
+  explicit MediaControlsResizeObserverCallback(MediaControls* controls)
+      : m_controls(controls) {
+    DCHECK(controls);
+  }
+  ~MediaControlsResizeObserverCallback() override = default;
+
+  void handleEvent(const HeapVector<Member<ResizeObserverEntry>>& entries,
+                   ResizeObserver* observer) override {
+    DCHECK_EQ(1u, entries.size());
+    DCHECK_EQ(entries[0]->target(), m_controls->m_mediaElement);
+    ClientRect* contentRect = entries[0]->contentRect();
+    m_controls->notifyElementSizeChanged(contentRect->width(),
+                                         contentRect->height());
+  }
+
+  DEFINE_INLINE_TRACE() {
+    visitor->trace(m_controls);
+    ResizeObserverCallback::trace(visitor);
+  }
+
+ private:
+  Member<MediaControls> m_controls;
+};
+
 MediaControls::MediaControls(HTMLMediaElement& mediaElement)
     : HTMLDivElement(mediaElement.document()),
       m_mediaElement(&mediaElement),
@@ -146,12 +188,19 @@ MediaControls::MediaControls(HTMLMediaElement& mediaElement)
       m_hideTimerBehaviorFlags(IgnoreNone),
       m_isMouseOverControls(false),
       m_isPausedForScrubbing(false),
-      m_panelWidthChangedTimer(TaskRunnerHelper::get(TaskType::UnspecedTimer,
-                                                     &mediaElement.document()),
-                               this,
-                               &MediaControls::panelWidthChangedTimerFired),
-      m_panelWidth(0),
-      m_keepShowingUntilTimerFires(false) {}
+      m_resizeObserver(ResizeObserver::create(
+          mediaElement.document(),
+          new MediaControlsResizeObserverCallback(this))),
+      m_sizingInitialized(false),
+      m_elementSizeChangedTimer(TaskRunnerHelper::get(TaskType::UnspecedTimer,
+                                                      &mediaElement.document()),
+                                this,
+                                &MediaControls::elementSizeChangedTimerFired),
+      m_effectiveWidth(0),
+      m_effectiveHeight(0),
+      m_keepShowingUntilTimerFires(false) {
+  m_resizeObserver->observe(m_mediaElement);
+}
 
 MediaControls* MediaControls::create(HTMLMediaElement& mediaElement,
                                      ShadowRoot& shadowRoot) {
@@ -788,25 +837,28 @@ void MediaControls::onExitedFullscreen() {
   startHideMediaControlsTimer();
 }
 
-void MediaControls::notifyPanelWidthChanged(const LayoutUnit& newWidth) {
-  // Don't bother to do any work if this matches the most recent panel
-  // width, since we're called after layout.
+void MediaControls::notifyElementSizeChanged(int newWidth, int newHeight) {
   // Note that this code permits a bad frame on resize, since it is
   // run after the relayout / paint happens.  It would be great to improve
   // this, but it would be even greater to move this code entirely to
   // JS and fix it there.
-  m_panelWidth = newWidth.toInt();
 
   // Adjust for effective zoom.
   if (!m_panel->layoutObject() || !m_panel->layoutObject()->style())
     return;
-  m_panelWidth =
-      ceil(m_panelWidth / m_panel->layoutObject()->style()->effectiveZoom());
 
-  m_panelWidthChangedTimer.startOneShot(0, BLINK_FROM_HERE);
+  int oldWidth = m_effectiveWidth;
+  int oldHeight = m_effectiveHeight;
+  m_effectiveWidth =
+      ceil(newWidth / m_panel->layoutObject()->style()->effectiveZoom());
+  m_effectiveHeight = newHeight;
+
+  // Don't bother to do any work if this matches the most recent size.
+  if (oldWidth != m_effectiveWidth || oldHeight != m_effectiveHeight)
+    m_elementSizeChangedTimer.startOneShot(0, BLINK_FROM_HERE);
 }
 
-void MediaControls::panelWidthChangedTimerFired(TimerBase*) {
+void MediaControls::elementSizeChangedTimerFired(TimerBase*) {
   computeWhichControlsFit();
 }
 
@@ -834,7 +886,7 @@ void MediaControls::computeWhichControlsFit() {
   // element.
   const int sliderMargin = 36;  // Sliders have 18px margin on each side.
 
-  if (!m_panelWidth) {
+  if (!m_effectiveWidth) {
     // No layout yet -- hide everything, then make them show up later.
     // This prevents the wrong controls from being shown briefly
     // immediately after the first layout and paint, but before we have
@@ -879,7 +931,7 @@ void MediaControls::computeWhichControlsFit() {
       width += sliderMargin;
     element->shouldShowButtonInOverflowMenu(false);
     if (element->isWanted()) {
-      if (usedWidth + width <= m_panelWidth) {
+      if (usedWidth + width <= m_effectiveWidth) {
         element->setDoesFit(true);
         usedWidth += width;
       } else {
@@ -907,13 +959,20 @@ void MediaControls::computeWhichControlsFit() {
       if ((firstDisplacedElement == m_timeline.get()) ||
           (firstDisplacedElement == m_volumeSlider.get()))
         width += sliderMargin;
-      if (usedWidth + width <= m_panelWidth)
+      if (usedWidth + width <= m_effectiveWidth)
         firstDisplacedElement->setDoesFit(true);
     }
   } else if (overflowElements.size() == 1) {
     m_overflowMenu->setIsWanted(false);
     overflowElements.front()->setDoesFit(true);
   }
+
+  // Decide if the overlay play button fits.
+  if (m_effectiveWidth && m_effectiveHeight && m_overlayPlayButton) {
+    bool doesFit = m_effectiveWidth >= kMinWidthForOverlayPlayButton &&
+                   m_effectiveHeight >= kMinHeightForOverlayPlayButton;
+    m_overlayPlayButton->setDoesFit(doesFit);
+  }
 }
 
 void MediaControls::invalidate(Element* element) {
@@ -935,6 +994,11 @@ void MediaControls::networkStateChanged() {
   invalidate(m_volumeSlider);
 }
 
+void MediaControls::onLayout(int width, int height) {
+  if (!m_sizingInitialized)
+    notifyElementSizeChanged(width, height);

[mlamouri (slow - plz ping), 2017/02/27 18:22:58]

I'm a bit concerned by this because you basically could use the `onLayout`
callback for everything it seems and we might actually be spending more
resources by using both LayoutMedia and the ResizeObserver. I understand that
the ResizeObserver doesn't seem to be doing everything we want here and I think
we should file a bug or at least find a solution.

However, in the context of this change, as I said before, using LayoutMedia
would be fine but I don't think there is much benefit is this hybrid solution :(
I'm happy to help chase down the ResizeObserver folks to see with them what we
can do here.

[steimel, 2017/02/28 00:59:47]

Done.

+}
+
 bool MediaControls::overflowMenuVisible() {
   return m_overflowList ? m_overflowList->isWanted() : false;
 }
@@ -957,6 +1021,7 @@ void MediaControls::hideAllMenus() {
 }
 
 DEFINE_TRACE(MediaControls) {
+  visitor->trace(m_resizeObserver);
   visitor->trace(m_mediaElement);
   visitor->trace(m_panel);
   visitor->trace(m_overlayPlayButton);