Reland of Android: support multiple displays on C++ side

ui/display/BUILD.gn

Index: ui/display/BUILD.gn
diff --git a/ui/display/BUILD.gn b/ui/display/BUILD.gn
index a3f8cf5f370b768bd68c5c191bb1e1278833b7c8..1bb487a481e11dbbc5b0ed0b0de855184a6c004c 100644
--- a/ui/display/BUILD.gn
+++ b/ui/display/BUILD.gn
@@ -3,11 +3,11 @@
 # found in the LICENSE file.
 
 import("//build/config/ui.gni")
+import("//build/config/android/rules.gni")
 import("//testing/test.gni")
 
 component("display") {
   sources = [
-    "android/screen_android.cc",
     "chromeos/apply_content_protection_task.cc",
     "chromeos/apply_content_protection_task.h",
     "chromeos/configure_displays_task.cc",
@@ -69,6 +69,15 @@ component("display") {
     "win/screen_win_display.h",
   ]
 
+  if (is_android && !use_aura) {

[boliu, 2016/10/27 22:17:49]

aura + android isn't a thing anymore, and android directory stuff should already
be only be included on android, so don't need this conditional

[Tima Vaisburd, 2016/10/31 23:36:15]

display_android_manager.{cc,h} are included unconditionally,
jni_registrar.{cc,h} are removed altogether.

+    sources += [
+      "android/display_android_manager.cc",
+      "android/display_android_manager.h",
+      "android/jni_registrar.cc",
+      "android/jni_registrar.h",
+    ]
+  }
+
   defines = [ "DISPLAY_IMPLEMENTATION" ]
 
   public_deps = [
@@ -84,6 +93,10 @@ component("display") {
     "//ui/gfx/geometry",
   ]
 
+  if (is_android) {
+    deps += [ ":display_jni_headers" ]
+  }
+
   if (is_chromeos && use_x11) {
     sources += [
       "chromeos/x11/display_mode_x11.cc",
@@ -115,9 +128,7 @@ component("display") {
   if (!use_aura) {
     sources -= [ "screen_aura.cc" ]
   }
-  if (is_android && use_aura) {
-    sources -= [ "android/screen_android.cc" ]
-  }
+
   if (is_mac) {
     libs = [
       "AppKit.framework",
@@ -126,6 +137,13 @@ component("display") {
   }
 }
 
+generate_jni("display_jni_headers") {
+  sources = [
+    "../../ui/android/java/src/org/chromium/ui/display/DisplayAndroidManager.java",

[Tima Vaisburd, 2016/10/27 07:55:58]

The path that start with ".." is probably bad, shall we move DisplayAndroid.java
and DisplayAndroidManager.java under ui/display/android ?

[mthiesse, 2016/10/27 14:30:30]

Do you mean to
ui/display/android/java/src/org/chromium/ui/display/DisplayAndroidManager.java?

I don't think we can move java source out of a java/src folder.

[Tima Vaisburd, 2016/10/27 17:56:24]

I guess we could repeat the hierarchy under this ui/display/android, but I did
not try.

+  ]
+  jni_package = "display"
+}
+
 static_library("test_support") {
   testonly = true
   sources = [