Introduce ChromeVR to Chrome on Android (behind a build flag)

This CL implements the following:
1. Adds a new activity called VrActivity. It extends from AsyncInitializationActivity
and can only be launched from Daydream app.
2. Adds a VrShell and its native part. VrShell has a GLSurfaceView as presentation
view for drawing left and right images and an inheriated(from GvrLayout) scanline
racing view(another GLSurfaceView).
3. Created a texture quad that is reserved for compositor to use to output content
frames. The quad is positioned at (0.0, 0.0, -1.0)

Known issue:
1. The quad is black as we haven't hookup a compositor to draw frames
2. tabs are not shared with ChromeTabbedActivity

To test this, add "enable_vr_shell=true" in your gn args.

BUG=638642

Review-Url: https://codereview.chromium.org/2252103002
Cr-Commit-Position: refs/heads/master@{#414890}
diff --git a/chrome/android/java_sources.gni b/chrome/android/java_sources.gni
index 989ecfb..19eb206 100644
--- a/chrome/android/java_sources.gni
+++ b/chrome/android/java_sources.gni
@@ -1062,6 +1062,11 @@
   "java/src/org/chromium/chrome/browser/widget/newtab/NewTabButton.java",
 ]
 
+chrome_vr_java_sources = [
+  "java/src/org/chromium/chrome/browser/VrActivity.java",
+  "java/src/org/chromium/chrome/browser/vr_shell/VrShell.java",
+]
+
 chrome_test_java_sources = [
   "javatests/src/org/chromium/base/test/util/parameter/ParameterizedTestAnnotationTest.java",
   "javatests/src/org/chromium/base/test/util/parameter/ParameterizedTestClassAnnotationInheritanceTest.java",