Adds keyboard functionality for videos.

third_party/WebKit/Source/modules/media_controls/MediaControlsImpl.cpp

Index: third_party/WebKit/Source/modules/media_controls/MediaControlsImpl.cpp
diff --git a/third_party/WebKit/Source/modules/media_controls/MediaControlsImpl.cpp b/third_party/WebKit/Source/modules/media_controls/MediaControlsImpl.cpp
index 2f32c0510fc28434d2ae7adb85c8c19b4a0dfffc..61085d771e897a2ae8c2c87657a8548bd7d42e39 100644
--- a/third_party/WebKit/Source/modules/media_controls/MediaControlsImpl.cpp
+++ b/third_party/WebKit/Source/modules/media_controls/MediaControlsImpl.cpp
@@ -37,6 +37,7 @@
 #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"
@@ -852,6 +853,23 @@ void MediaControlsImpl::DefaultEventHandler(Event* event) {
   if (event->type() == EventTypeNames::focusin ||
       event->type() == EventTypeNames::input)
     ResetHideMediaControlsTimer();
+
+  if (event->IsKeyboardEvent() && !IsSpatialNavigationActive()) {

[mlamouri (slow - plz ping), 2017/05/24 08:49:15]

Would it make sense to allow "enter" and "space" to be used with spatial
navigation enabled?

[lethalantidote, 2017/05/24 18:46:08]

Maybe, but wouldn't that cause inconsistency? It's only one more button press to
get the same effect, and it would be the same expectation for all controls (User
has to navigate to the control versus operate on the video itself). I think that
this might be something we would want Rachel to have input on.

[mlamouri (slow - plz ping), 2017/05/30 10:22:41]

I have no strong opinion on this. Whatever sounds right to you. I see two valid
options:
1. we drop all the keyboards when spatial navigation is enabled
2. we drop all the arrow keys when spatial navigation is enabled

+    const String& key = ToKeyboardEvent(event)->key();
+    if (key == "Enter" || ToKeyboardEvent(event)->keyCode() == ' ') {
+      play_button_->OnMediaKeyboardEvent(event);
+      return;
+    }
+    if (key == "ArrowLeft" || key == "ArrowRight" || key == "Home" ||
+        key == "End") {
+      timeline_->OnMediaKeyboardEvent(event);
+      return;
+    }
+    if (key == "ArrowDown" || key == "ArrowUp") {
+      volume_slider_->OnMediaKeyboardEvent(event);
+      return;
+    }
+  }
 }
 
 void MediaControlsImpl::HideMediaControlsTimerFired(TimerBase*) {