Make WebView work for external displays (over Presentations).

ui/android/screen_android.cc

Index: ui/android/screen_android.cc
diff --git a/ui/gfx/screen_android.cc b/ui/android/screen_android.cc
similarity index 54%
rename from ui/gfx/screen_android.cc
rename to ui/android/screen_android.cc
index c286e603f2d8b621662a47f7cce4a0755cbd92a0..83b10c0410a1bc0f73802ddea12f27f0b6243487 100644
--- a/ui/gfx/screen_android.cc
+++ b/ui/android/screen_android.cc
@@ -5,12 +5,36 @@
 #include "ui/gfx/screen.h"
 
 #include "base/logging.h"
+#include "ui/android/view_android.h"
+#include "ui/android/window_android.h"
 #include "ui/gfx/android/device_display_info.h"
 #include "ui/gfx/display.h"
 #include "ui/gfx/geometry/size_conversions.h"
 
 namespace gfx {
 
+gfx::Display DisplayFromDeviceDisplayInfo(
+    const gfx::DeviceDisplayInfo& device_info) {
+  const float device_scale_factor = device_info.GetDIPScale();
+  // Note: GetPhysicalDisplayWidth/Height() does not subtract window
+  // decorations etc. Use it instead of GetDisplayWidth/Height() when
+  // available.
+  const gfx::Rect bounds_in_pixels =
+      gfx::Rect(device_info.GetPhysicalDisplayWidth()
+                    ? device_info.GetPhysicalDisplayWidth()
+                    : device_info.GetDisplayWidth(),
+                device_info.GetPhysicalDisplayHeight()
+                    ? device_info.GetPhysicalDisplayHeight()
+                    : device_info.GetDisplayHeight());
+  const gfx::Rect bounds_in_dip = gfx::Rect(gfx::ToCeiledSize(
+      gfx::ScaleSize(bounds_in_pixels.size(), 1.0f / device_scale_factor)));
+  gfx::Display display(0, bounds_in_dip);
+  if (!gfx::Display::HasForceDeviceScaleFactor())
+    display.set_device_scale_factor(device_scale_factor);
+  display.SetRotationAsDegree(device_info.GetRotationDegrees());
+  return display;
+}
+
 class ScreenAndroid : public Screen {
  public:
   ScreenAndroid() {}
@@ -29,29 +53,16 @@ class ScreenAndroid : public Screen {
 
   gfx::Display GetPrimaryDisplay() const override {
     gfx::DeviceDisplayInfo device_info;
-    const float device_scale_factor = device_info.GetDIPScale();
-    // Note: GetPhysicalDisplayWidth/Height() does not subtract window
-    // decorations etc. Use it instead of GetDisplayWidth/Height() when
-    // available.
-    const gfx::Rect bounds_in_pixels =
-        gfx::Rect(device_info.GetPhysicalDisplayWidth()
-                      ? device_info.GetPhysicalDisplayWidth()
-                      : device_info.GetDisplayWidth(),
-                  device_info.GetPhysicalDisplayHeight()
-                      ? device_info.GetPhysicalDisplayHeight()
-                      : device_info.GetDisplayHeight());
-    const gfx::Rect bounds_in_dip =
-        gfx::Rect(gfx::ToCeiledSize(gfx::ScaleSize(
-            bounds_in_pixels.size(), 1.0f / device_scale_factor)));
-    gfx::Display display(0, bounds_in_dip);
-    if (!gfx::Display::HasForceDeviceScaleFactor())
-      display.set_device_scale_factor(device_scale_factor);
-    display.SetRotationAsDegree(device_info.GetRotationDegrees());
-    return display;
+    return DisplayFromDeviceDisplayInfo(device_info);
   }
 
   gfx::Display GetDisplayNearestWindow(gfx::NativeView view) const override {
-    return GetPrimaryDisplay();
+    if (view) {
+      return DisplayFromDeviceDisplayInfo(
+          view->GetWindowAndroid()->GetDeviceDisplayInfo());
+    } else {
+      return GetPrimaryDisplay();
+    }
   }
 
   gfx::Display GetDisplayNearestPoint(const gfx::Point& point) const override {