Adds visual viewport size override to DevTools Emulation protocol.

content/browser/devtools/protocol/emulation_handler.cc

Index: content/browser/devtools/protocol/emulation_handler.cc
diff --git a/content/browser/devtools/protocol/emulation_handler.cc b/content/browser/devtools/protocol/emulation_handler.cc
index 12c377a4fc84eab5396d2d195ded5158134a463f..f498f335592675d5e5818d054ccf19010c14a739 100644
--- a/content/browser/devtools/protocol/emulation_handler.cc
+++ b/content/browser/devtools/protocol/emulation_handler.cc
@@ -146,7 +146,9 @@ Response EmulationHandler::SetDeviceMetricsOverride(
     const int* screen_height,
     const int* position_x,
     const int* position_y,
-    const std::unique_ptr<base::DictionaryValue>& screen_orientation) {
+    const std::unique_ptr<base::DictionaryValue>& screen_orientation,
+    const int* visual_viewport_width,
+    const int* visual_viewport_height) {
   const static int max_size = 10000000;
   const static double max_scale = 10;
   const static int max_orientation_angle = 360;
@@ -207,6 +209,15 @@ Response EmulationHandler::SetDeviceMetricsOverride(
     }
   }
 
+  if ((visual_viewport_width &&
+       (*visual_viewport_width < 0 || *visual_viewport_width > max_size)) ||
+      (visual_viewport_height &&
+       (*visual_viewport_height < 0 || *visual_viewport_height > max_size))) {
+    return Response::InvalidParams(
+        "Visual viewport dimensions must be positive, not greater than " +
+        base::IntToString(max_size));
+  }
+
   blink::WebDeviceEmulationParams params;
   params.screenPosition = mobile ? blink::WebDeviceEmulationParams::Mobile :
       blink::WebDeviceEmulationParams::Desktop;
@@ -223,6 +234,9 @@ Response EmulationHandler::SetDeviceMetricsOverride(
       optional_offset_y ? *optional_offset_y : 0.f);
   params.screenOrientationType = orientationType;
   params.screenOrientationAngle = orientationAngle;
+  params.visualViewportSize =
+      blink::WebSize(visual_viewport_width ? *visual_viewport_width : 0,
+                     visual_viewport_height ? *visual_viewport_height : 0);
 
   if (device_emulation_enabled_ && params == device_emulation_params_)
     return Response::OK();