Adds keyboard functionality for videos.

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 6fcf2642e672bbb9fa145f243b43bcf7045fa993..dcce3bdcff06bb7e17031912565277e840bd8509 100644
--- a/third_party/WebKit/Source/core/html/shadow/MediaControls.cpp
+++ b/third_party/WebKit/Source/core/html/shadow/MediaControls.cpp
@@ -33,6 +33,7 @@
 #include "core/dom/ResizeObserverCallback.h"
 #include "core/dom/ResizeObserverEntry.h"
 #include "core/dom/TaskRunnerHelper.h"
+#include "core/events/KeyboardEvent.h"
 #include "core/events/MouseEvent.h"
 #include "core/frame/Settings.h"
 #include "core/frame/UseCounter.h"
@@ -751,6 +752,31 @@ void MediaControls::defaultEventHandler(Event* event) {
       startHideMediaControlsTimer();
     return;
   }
+
+  if (event->isKeyboardEvent()) {
+    if (!mediaElement().paused()) {
+      makeOpaque();
+      if (shouldHideMediaControls())
+        startHideMediaControlsTimer();
+    }
+
+    int key = toKeyboardEvent(event)->keyCode();
+    switch (key) {
+      case ('\r'):
+      case (' '):
+        m_playButton->defaultEventHandler(event);
+        return;
+      case (37):
+      case (39):
+        timelineElement()->defaultEventHandler(event);
+        onTimeUpdate();

[mlamouri (slow - plz ping), 2017/03/16 12:17:22]

Shouldn't this be called automatically?

[CJ, 2017/03/16 20:08:28]

Didn't seem to work without it. Will double check. 

+        return;
+      case (38):
+      case (40):
+        volumeSliderElement()->defaultEventHandler(event);

[mlamouri (slow - plz ping), 2017/03/16 12:17:22]

For the issue you mention, is onVolueChange called? What happens if you manually
call it?

[CJ, 2017/03/16 20:08:28]

I tried that. Instead of refreshing the blue line after reshowing, it starts the
refresh after it fades away.

+        return;
+    }
+  }
 }
 
 void MediaControls::hideMediaControlsTimerFired(TimerBase*) {
@@ -806,6 +832,7 @@ void MediaControls::onVolumeChange() {
   m_volumeSlider->setIsWanted(mediaElement().hasAudio() &&
                               !preferHiddenVolumeControls(document()));
   m_muteButton->setIsWanted(mediaElement().hasAudio());
+  startHideMediaControlsTimer();

[mlamouri (slow - plz ping), 2017/03/16 12:17:22]

Why are you hiding this?

[CJ, 2017/03/16 20:08:28]

Not sure why that is there. Removing.

 }
 
 void MediaControls::onFocusIn() {