Add VR Shell animation classes and unit test.

chrome/browser/android/vr_shell/BUILD.gn

Index: chrome/browser/android/vr_shell/BUILD.gn
diff --git a/chrome/browser/android/vr_shell/BUILD.gn b/chrome/browser/android/vr_shell/BUILD.gn
index 3dfc8c6fb931b7ddcce342658924f071dd373f5f..2a815e8cc054e569960e20781b2695066025b852 100644
--- a/chrome/browser/android/vr_shell/BUILD.gn
+++ b/chrome/browser/android/vr_shell/BUILD.gn
@@ -4,6 +4,7 @@
 
 import("//build/config/android/rules.gni")
 import("//chrome/common/features.gni")
+import("//testing/test.gni")
 
 assert(enable_vr_shell && android_java_ui)
 
@@ -39,3 +40,24 @@ generate_jni("vr_shell_jni_headers") {
   ]
   jni_package = "vr_shell"
 }
+
+test("vr_shell_unittests") {

[bshe, 2016/09/12 15:38:26]

I assume you have a follow up CL that config bot to build and run these tests?
It would be nice to file a bug and refer to it here.

[cjgrant, 2016/09/13 17:32:15]

Will do.  I'll read up on this.

+  sources = [
+    "animation.cc",

[bshe, 2016/09/12 15:38:26]

no unittest related file should be moved to vr_shell? And then you can probably
depend on vr_shell to pull the dependency. 

[cjgrant, 2016/09/13 17:32:15]

Good call.  I initially liked that the unit test target could compile without
vr_shell's dependencies, but this would get uglier as we add more tests.  And
this is the convention too.  Thanks.

+    "animation.h",
+    "easing.cc",
+    "easing.h",
+    "ui_elements.cc",
+    "ui_elements.h",
+    "ui_elements_unittest.cc",
+    "vr_math.cc",
+    "vr_math.h",
+  ]
+
+  deps = [
+    "//base/test:run_all_unittests",
+    "//base/test:test_support",
+    "//testing/gtest",
+    "//ui/gfx/geometry",
+  ]
+}