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 89f8b67ed7531bd47f8619d88d91b4e59aeef7df..60856e0ecc30d59615ed71c031ef76b9a1730743 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;
+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
+
 // If you change this value, then also update the corresponding value in
 // LayoutTests/media/media-controls.js.
 static const double timeWithoutMouseMovementBeforeHidingMediaControls = 3;
@@ -106,8 +121,37 @@ class MediaControls::BatchedControlUpdate {
 // Count of number open batches for controls visibility.
 int MediaControls::BatchedControlUpdate::s_batchDepth = 0;
 
+class MediaControls::MediaControlsResizeObserverCallback
+    : public ResizeObserverCallback {
+ public:
+  explicit MediaControlsResizeObserverCallback(MediaControls* controls)
+      : m_controls(controls) {
+    DCHECK(controls);
+  }
+  ~MediaControlsResizeObserverCallback() override{};

[mlamouri (slow - plz ping), 2017/02/22 11:48:08]

nit: s/{};/ = default;/

[steimel, 2017/02/23 00:53:48]

Done.

+
+  void handleEvent(const HeapVector<Member<ResizeObserverEntry>>& entries,
+                   ResizeObserver* observer) override {
+    for (const auto& entry : entries) {

[mlamouri (slow - plz ping), 2017/02/22 11:48:08]

Is more than one entry expected? Should we DCHECK() for entries.size == 1?

[steimel, 2017/02/23 00:53:48]

Discussed offline. After looking at the spec, there will only be one entry per
observed element, and since we only observe one element, yes we should DCHECK

+      m_controls->notifyPanelSizeChanged((int)entry->contentRect()->width(),
+                                         (int)entry->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_resizeObserver(ResizeObserver::create(
+          mediaElement.document(),
+          new MediaControlsResizeObserverCallback(this))),
       m_mediaElement(&mediaElement),
       m_overlayEnclosure(nullptr),
       m_overlayPlayButton(nullptr),
@@ -138,12 +182,15 @@ 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_panelSizeChangedTimer(TaskRunnerHelper::get(TaskType::UnspecedTimer,
+                                                    &mediaElement.document()),
+                              this,
+                              &MediaControls::panelSizeChangedTimerFired),
       m_panelWidth(0),
-      m_keepShowingUntilTimerFires(false) {}
+      m_panelHeight(0),
+      m_keepShowingUntilTimerFires(false) {
+  m_resizeObserver->observe(m_mediaElement);

[mlamouri (slow - plz ping), 2017/02/22 11:48:08]

Would it make sense to initialise the current size in the case the resize
observer is set up after the first layout, thus would not notify us of the
current size?

[steimel, 2017/02/23 00:53:48]

Discussed offline, but re-adding some code in LayoutMedia to inform the
mediacontrols of layouts to handle initialization

+}
 
 MediaControls* MediaControls::create(HTMLMediaElement& mediaElement,
                                      ShadowRoot& shadowRoot) {
@@ -781,25 +828,27 @@ void MediaControls::onExitedFullscreen() {
   startHideMediaControlsTimer();
 }
 
-void MediaControls::notifyPanelWidthChanged(const LayoutUnit& newWidth) {
+void MediaControls::notifyPanelSizeChanged(int newWidth, int newHeight) {
   // Don't bother to do any work if this matches the most recent panel
-  // width, since we're called after layout.
+  // size, since we're called after layout.
   // 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();
+  m_panelWidth = newWidth;
+  m_panelHeight = newHeight;

[mlamouri (slow - plz ping), 2017/02/22 11:48:08]

Is it really still the panel width/height? Shouldn't that be the media element
instead?

[steimel, 2017/02/23 00:53:48]

Done.

 
   // 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);
+  m_panelSizeChangedTimer.startOneShot(0, BLINK_FROM_HERE);
 }
 
-void MediaControls::panelWidthChangedTimerFired(TimerBase*) {
+void MediaControls::panelSizeChangedTimerFired(TimerBase*) {
   computeWhichControlsFit();
 }
 
@@ -910,6 +959,13 @@ void MediaControls::computeWhichControlsFit() {
     m_overflowMenu->setIsWanted(false);
     overflowElements.front()->setDoesFit(true);
   }
+
+  // Decide if the overlay play button fits.
+  if (m_panelWidth && m_panelHeight && m_overlayPlayButton) {
+    bool doesFit = m_panelWidth >= kMinWidthForOverlayPlayButton &&
+                   m_panelHeight >= kMinHeightForOverlayPlayButton;
+    m_overlayPlayButton->setDoesFit(doesFit);
+  }
 }
 
 void MediaControls::invalidate(Element* element) {
@@ -953,6 +1009,7 @@ void MediaControls::hideAllMenus() {
 }
 
 DEFINE_TRACE(MediaControls) {
+  visitor->trace(m_resizeObserver);
   visitor->trace(m_mediaElement);
   visitor->trace(m_panel);
   visitor->trace(m_overlayPlayButton);