Updates volume to change by .05 increments.

BUG=730519

Review-Url: https://codereview.chromium.org/2938913002
Cr-Commit-Position: refs/heads/master@{#488373}

third_party/WebKit/LayoutTests/media/controls/controls-video-keynav.html

@@ -24,11 +24,17 @@ async_test(function(t) {
       eventSender.keyDown("Enter");
       assert_false(video.paused);
 
-      // 'Down' reduces volume.
+      // 'Down' reduces volume by .05.
       eventSender.keyDown("ArrowDown");
-      assert_less_than(video.volume, 1);
+      assert_equals(video.volume, .95);
+
+      eventSender.keyDown("ArrowDown");
+      assert_equals(video.volume, .9);
+
+      // 'Up' increases volume by .05
+      eventSender.keyDown("ArrowUp");
+      assert_equals(video.volume, .95);
 
-      // 'Up' increases volume.
       eventSender.keyDown("ArrowUp");
       assert_equals(video.volume, 1);
 

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

@@ -870,7 +870,8 @@ void MediaControlsImpl::DefaultEventHandler(Event* event) {
       return;
     }
     if (key == "ArrowDown" || key == "ArrowUp") {
-      volume_slider_->OnMediaKeyboardEvent(event);
+      for (int i = 0; i < 5; i++)
+        volume_slider_->OnMediaKeyboardEvent(event);
       return;
     }
   }