aura: Unify WindowTreeHost for some platforms

ui/aura/BUILD.gn

Index: ui/aura/BUILD.gn
diff --git a/ui/aura/BUILD.gn b/ui/aura/BUILD.gn
index 2aa15ec9e600261c9165b0e41a1ad7925fddc0a9..d74892029a24e0d51bac112c3caad79300769682 100644
--- a/ui/aura/BUILD.gn
+++ b/ui/aura/BUILD.gn
@@ -86,8 +86,8 @@ component("aura") {
     "window_tree_host_mac.h",
     "window_tree_host_mac.mm",
     "window_tree_host_observer.h",
-    "window_tree_host_win.cc",
-    "window_tree_host_win.h",
+    "window_tree_host_platform.cc",
+    "window_tree_host_platform.h",
     "window_tree_host_x11.cc",
     "window_tree_host_x11.h",
   ]
@@ -137,14 +137,20 @@ component("aura") {
     ]
   }
 
-  if (use_ozone) {
-    sources += [
-      "window_tree_host_ozone.cc",
-      "window_tree_host_ozone.h",
+  if ((is_mac || use_x11) && !use_ozone) {

[mfomitchev, 2015/10/09 21:24:18]

(!is_win && !use_ozone && !is_android)?
IMHO better to list all platforms that need this rather than all platforms that
don't, since the set of platforms may change.

+    sources -= [
+      "window_tree_host_platform.cc",
+      "window_tree_host_platform.h",
     ]
 
     deps += [ "//ui/ozone" ]
   }
+
+  if (is_android) {
+    deps += [
+      "//ui/platform_window/android",

[mfomitchev, 2015/10/09 21:24:18]

I also had to add "//ui/platform_window/android:platform_window_java" here to
make it run, otherwise it crashed at runtime...

[no sievers, 2015/10/09 21:42:23]

oops forgot this

+    ]
+  }
 }
 
 source_set("test_support") {