Create a ControlFeature for Blimp

Add a basic ControlFeature class for blimp to allow for passing resize
messages to the engine.

BUG=

Review URL: https://codereview.chromium.org/1496013004

Cr-Commit-Position: refs/heads/master@{#364259}

25 files changed, 402 insertions, 35 deletions

diff --git a/blimp/client/BUILD.gn b/blimp/client/BUILD.gn
index ac1e0ac..3858bd3 100644
--- a/blimp/client/BUILD.gn
+++ b/blimp/client/BUILD.gn
@@ -30,6 +30,8 @@ component("blimp_client") {
     "session/navigation_feature.h",
     "session/render_widget_feature.cc",
     "session/render_widget_feature.h",
+    "session/tab_control_feature.cc",
+    "session/tab_control_feature.h",
   ]
 
   defines = [ "BLIMP_CLIENT_IMPLEMENTATION=1" ]
@@ -62,6 +64,7 @@ source_set("unit_tests") {
   sources = [
     "session/navigation_feature_unittest.cc",
     "session/render_widget_feature_unittest.cc",
+    "session/tab_control_feature_unittest.cc",
   ]
 
   deps = [
@@ -105,6 +108,7 @@ if (is_android) {
       "android/java/src/org/chromium/blimp/BlimpLibraryLoader.java",
       "android/java/src/org/chromium/blimp/BlimpView.java",
       "android/java/src/org/chromium/blimp/session/BlimpClientSession.java",
+      "android/java/src/org/chromium/blimp/session/TabControlFeature.java",
       "android/java/src/org/chromium/blimp/toolbar/Toolbar.java",
     ]
 
@@ -189,6 +193,7 @@ if (is_android) {
       "android/java/src/org/chromium/blimp/BlimpRendererActivity.java",
       "android/java/src/org/chromium/blimp/BlimpView.java",
       "android/java/src/org/chromium/blimp/session/BlimpClientSession.java",
+      "android/java/src/org/chromium/blimp/session/TabControlFeature.java",
       "android/java/src/org/chromium/blimp/toolbar/Toolbar.java",
       "android/java/src/org/chromium/blimp/toolbar/UrlBar.java",
     ]
@@ -236,6 +241,8 @@ if (is_android) {
       "compositor/blimp_compositor_android.h",
       "session/blimp_client_session_android.cc",
       "session/blimp_client_session_android.h",
+      "session/tab_control_feature_android.cc",
+      "session/tab_control_feature_android.h",
     ]
 
     libs = [ "android" ]
diff --git a/blimp/client/android/blimp_jni_registrar.cc b/blimp/client/android/blimp_jni_registrar.cc
index 26f6b02..185a5f3 100644
--- a/blimp/client/android/blimp_jni_registrar.cc
+++ b/blimp/client/android/blimp_jni_registrar.cc
@@ -9,6 +9,7 @@
 #include "blimp/client/android/blimp_view.h"
 #include "blimp/client/android/toolbar.h"
 #include "blimp/client/session/blimp_client_session_android.h"
+#include "blimp/client/session/tab_control_feature_android.h"
 
 namespace {
 
@@ -18,6 +19,7 @@ base::android::RegistrationMethod kBlimpRegistrationMethods[] = {
     {"BlimpView", blimp::BlimpView::RegisterJni},
     {"BlimpClientSessionAndroid",
      blimp::BlimpClientSessionAndroid::RegisterJni},
+    {"TabControlFeatureAndroid", blimp::TabControlFeatureAndroid::RegisterJni},
 };
 
 }  // namespace
diff --git a/blimp/client/android/blimp_view.cc b/blimp/client/android/blimp_view.cc
index 6abbfcc..3fdbe26 100644
--- a/blimp/client/android/blimp_view.cc
+++ b/blimp/client/android/blimp_view.cc
@@ -14,7 +14,6 @@
 
 namespace blimp {
 
-// static
 static jlong Init(JNIEnv* env,
                   const JavaParamRef<jobject>& jobj,
                   const JavaParamRef<jobject>& blimp_client_session,
diff --git a/blimp/client/android/java/src/org/chromium/blimp/BlimpRendererActivity.java b/blimp/client/android/java/src/org/chromium/blimp/BlimpRendererActivity.java
index 0558b96..6641c39 100644
--- a/blimp/client/android/java/src/org/chromium/blimp/BlimpRendererActivity.java
+++ b/blimp/client/android/java/src/org/chromium/blimp/BlimpRendererActivity.java
@@ -14,6 +14,7 @@ import org.chromium.blimp.auth.RetryingTokenSource;
 import org.chromium.blimp.auth.TokenSource;
 import org.chromium.blimp.auth.TokenSourceImpl;
 import org.chromium.blimp.session.BlimpClientSession;
+import org.chromium.blimp.session.TabControlFeature;
 import org.chromium.blimp.toolbar.Toolbar;
 import org.chromium.ui.widget.Toast;
 
@@ -30,6 +31,7 @@ public class BlimpRendererActivity extends Activity implements BlimpLibraryLoade
     private BlimpView mBlimpView;
     private Toolbar mToolbar;
     private BlimpClientSession mBlimpClientSession;
+    private TabControlFeature mTabControlFeature;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
@@ -50,6 +52,11 @@ public class BlimpRendererActivity extends Activity implements BlimpLibraryLoade
 
     @Override
     protected void onDestroy() {
+        if (mTabControlFeature != null) {
+            mTabControlFeature.destroy();
+            mTabControlFeature = null;
+        }
+
         if (mBlimpView != null) {
             mBlimpView.destroyRenderer();
             mBlimpView = null;
@@ -115,6 +122,8 @@ public class BlimpRendererActivity extends Activity implements BlimpLibraryLoade
 
         mToolbar = (Toolbar) findViewById(R.id.toolbar);
         mToolbar.initialize(mBlimpClientSession);
+
+        mTabControlFeature = new TabControlFeature(mBlimpClientSession, mBlimpView);
     }
 
     // TokenSource.Callback implementation.
diff --git a/blimp/client/android/java/src/org/chromium/blimp/session/BlimpClientSession.java b/blimp/client/android/java/src/org/chromium/blimp/session/BlimpClientSession.java
index 3501c5f..cc93680 100644
--- a/blimp/client/android/java/src/org/chromium/blimp/session/BlimpClientSession.java
+++ b/blimp/client/android/java/src/org/chromium/blimp/session/BlimpClientSession.java
@@ -24,10 +24,10 @@ public class BlimpClientSession {
      * Destroys the native BlimpClientSession.  This class should not be used after this is called.
      */
     public void destroy() {
-        if (mNativeBlimpClientSessionAndroidPtr != 0) {
-            nativeDestroy(mNativeBlimpClientSessionAndroidPtr);
-            mNativeBlimpClientSessionAndroidPtr = 0;
-        }
+        if (mNativeBlimpClientSessionAndroidPtr == 0) return;
+
+        nativeDestroy(mNativeBlimpClientSessionAndroidPtr);
+        mNativeBlimpClientSessionAndroidPtr = 0;
     }
 
     // Methods that are called by native via JNI.
diff --git a/blimp/client/android/java/src/org/chromium/blimp/session/TabControlFeature.java b/blimp/client/android/java/src/org/chromium/blimp/session/TabControlFeature.java
new file mode 100644
index 0000000..d9847af
--- /dev/null
+++ b/blimp/client/android/java/src/org/chromium/blimp/session/TabControlFeature.java
@@ -0,0 +1,72 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.blimp.session;
+
+import android.view.View;
+
+import org.chromium.base.annotations.JNINamespace;
+
+/**
+ * A Java representation of the native ControlFeature class.  Provides easy access for Java control
+ * UI to interact with the native content-lite feature proxy and talk to the engine.
+ */
+@JNINamespace("blimp")
+public class TabControlFeature implements View.OnLayoutChangeListener {
+    private final float mDpToPx;
+
+    private View mContentAreaView;
+    private long mNativeTabControlFeatureAndroidPtr;
+
+    /**
+     * Creates an instance of a {@link TabControlFeature}.  This will register with
+     * {@code contentAreaView} as a {@link android.view.View.OnLayoutChangeListener} and will
+     * unregister when {@link #destroy()} is called.
+     * @param blimpClientSession The {@link BlimpClientSession} that contains the content-lite
+     *                           features required by the native components of the
+     *                           {@link TabControlFeature}.
+     * @param contentAreaView    A {@link View} that represents the content area of the screen.
+     *                           This is used to notify the engine of the correct size of the web
+     *                           content area.
+     */
+    public TabControlFeature(BlimpClientSession blimpClientSession, View contentAreaView) {
+        mContentAreaView = contentAreaView;
+        mDpToPx = mContentAreaView.getContext().getResources().getDisplayMetrics().density;
+        mNativeTabControlFeatureAndroidPtr = nativeInit(blimpClientSession);
+
+        // Push down the current size of the content area view.
+        nativeOnContentAreaSizeChanged(mNativeTabControlFeatureAndroidPtr,
+                mContentAreaView.getWidth(), mContentAreaView.getHeight(), mDpToPx);
+    }
+
+    /**
+     * Tears down the native counterpart to this class and unregisters any {@link View} listeners.
+     * This class should not be used after this.
+     */
+    public void destroy() {
+        if (mContentAreaView != null) {
+            mContentAreaView.removeOnLayoutChangeListener(this);
+            mContentAreaView = null;
+        }
+
+        if (mNativeTabControlFeatureAndroidPtr != 0) {
+            nativeDestroy(mNativeTabControlFeatureAndroidPtr);
+            mNativeTabControlFeatureAndroidPtr = 0;
+        }
+    }
+
+    // View.OnLayoutChangeListener implementation.
+    @Override
+    public void onLayoutChange(View v, int left, int top, int right, int bottom,
+            int oldLeft, int oldTop, int oldRight, int oldBottom) {
+        if (mNativeTabControlFeatureAndroidPtr == 0) return;
+        nativeOnContentAreaSizeChanged(mNativeTabControlFeatureAndroidPtr, right - left,
+                bottom - top, mDpToPx);
+    }
+
+    private native long nativeInit(BlimpClientSession blimpClientSession);
+    private native void nativeDestroy(long nativeTabControlFeatureAndroid);
+    private native void nativeOnContentAreaSizeChanged(
+            long nativeTabControlFeatureAndroid, int width, int height, float dpToPx);
+}
\ No newline at end of file
diff --git a/blimp/client/android/toolbar.cc b/blimp/client/android/toolbar.cc
index 2de3b93..abb6962 100644
--- a/blimp/client/android/toolbar.cc
+++ b/blimp/client/android/toolbar.cc
@@ -5,9 +5,7 @@
 #include "blimp/client/android/toolbar.h"
 
 #include "base/android/jni_string.h"
-#include "base/lazy_instance.h"
 #include "blimp/client/session/blimp_client_session_android.h"
-#include "blimp/net/null_blimp_message_processor.h"
 #include "jni/Toolbar_jni.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/gfx/android/java_bitmap.h"
@@ -21,7 +19,6 @@ const int kDummyTabId = 0;
 
 }  // namespace
 
-// static
 static jlong Init(JNIEnv* env,
                   const JavaParamRef<jobject>& jobj,
                   const JavaParamRef<jobject>& blimp_client_session) {
diff --git a/blimp/client/compositor/blimp_compositor.cc b/blimp/client/compositor/blimp_compositor.cc
index 87d6a95..cc3b557 100644
--- a/blimp/client/compositor/blimp_compositor.cc
+++ b/blimp/client/compositor/blimp_compositor.cc
@@ -19,8 +19,6 @@
 #include "blimp/client/compositor/test/dummy_layer_driver.h"
 #include "blimp/client/session/render_widget_feature.h"
 #include "blimp/common/compositor/blimp_task_graph_runner.h"
-#include "blimp/net/blimp_message_multiplexer.h"
-#include "blimp/net/null_blimp_message_processor.h"
 #include "cc/layers/layer.h"
 #include "cc/layers/layer_settings.h"
 #include "cc/output/output_surface.h"
diff --git a/blimp/client/session/blimp_client_session.cc b/blimp/client/session/blimp_client_session.cc
index 1db97f7..f0fcd39 100644
--- a/blimp/client/session/blimp_client_session.cc
+++ b/blimp/client/session/blimp_client_session.cc
@@ -6,15 +6,20 @@
 
 #include "blimp/client/session/navigation_feature.h"
 #include "blimp/client/session/render_widget_feature.h"
+#include "blimp/client/session/tab_control_feature.h"
 #include "blimp/net/browser_connection_handler.h"
 
 namespace blimp {
 
 BlimpClientSession::BlimpClientSession()
     : connection_handler_(new BrowserConnectionHandler),
+      tab_control_feature_(new TabControlFeature),
       navigation_feature_(new NavigationFeature),
       render_widget_feature_(new RenderWidgetFeature) {
   // Connect the features with the network layer.
+  tab_control_feature_->set_outgoing_message_processor(
+        connection_handler_->RegisterFeature(BlimpMessage::CONTROL,
+                                             tab_control_feature_.get()));
   navigation_feature_->set_outgoing_message_processor(
       connection_handler_->RegisterFeature(BlimpMessage::NAVIGATION,
                                            navigation_feature_.get()));
@@ -32,6 +37,10 @@ BlimpClientSession::BlimpClientSession()
 
 BlimpClientSession::~BlimpClientSession() {}
 
+TabControlFeature* BlimpClientSession::GetTabControlFeature() const {
+  return tab_control_feature_.get();
+}
+
 NavigationFeature* BlimpClientSession::GetNavigationFeature() const {
   return navigation_feature_.get();
 }
diff --git a/blimp/client/session/blimp_client_session.h b/blimp/client/session/blimp_client_session.h
index 9aa2001..da8e74a 100644
--- a/blimp/client/session/blimp_client_session.h
+++ b/blimp/client/session/blimp_client_session.h
@@ -14,6 +14,7 @@ namespace blimp {
 class BrowserConnectionHandler;
 class NavigationFeature;
 class RenderWidgetFeature;
+class TabControlFeature;
 
 // BlimpClientSession represents a single active session of Blimp on the client
 // regardless of whether or not the client application is in the background or
@@ -27,6 +28,7 @@ class BLIMP_CLIENT_EXPORT BlimpClientSession {
  public:
   BlimpClientSession();
 
+  TabControlFeature* GetTabControlFeature() const;
   NavigationFeature* GetNavigationFeature() const;
   RenderWidgetFeature* GetRenderWidgetFeature() const;
 
@@ -38,6 +40,7 @@ class BLIMP_CLIENT_EXPORT BlimpClientSession {
   // glue the feature-specific handlers to the actual network connection.
   scoped_ptr<BrowserConnectionHandler> connection_handler_;
 
+  scoped_ptr<TabControlFeature> tab_control_feature_;
   scoped_ptr<NavigationFeature> navigation_feature_;
   scoped_ptr<RenderWidgetFeature> render_widget_feature_;
 
diff --git a/blimp/client/session/render_widget_feature_unittest.cc b/blimp/client/session/render_widget_feature_unittest.cc
index 2359a22..3e7752d 100644
--- a/blimp/client/session/render_widget_feature_unittest.cc
+++ b/blimp/client/session/render_widget_feature_unittest.cc
@@ -17,10 +17,6 @@
 #include "testing/gtest/include/gtest/gtest.h"
 
 using testing::_;
-using testing::InvokeArgument;
-using testing::Ref;
-using testing::Return;
-using testing::SaveArg;
 
 namespace blimp {
 
diff --git a/blimp/client/session/tab_control_feature.cc b/blimp/client/session/tab_control_feature.cc
new file mode 100644
index 0000000..15cbdd1
--- /dev/null
+++ b/blimp/client/session/tab_control_feature.cc
@@ -0,0 +1,45 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "blimp/client/session/tab_control_feature.h"
+
+#include "blimp/common/create_blimp_message.h"
+#include "blimp/common/proto/blimp_message.pb.h"
+#include "blimp/common/proto/control.pb.h"
+#include "blimp/common/proto/size.pb.h"
+#include "blimp/net/blimp_message_processor.h"
+#include "ui/gfx/geometry/size.h"
+
+namespace blimp {
+
+TabControlFeature::TabControlFeature() {}
+
+TabControlFeature::~TabControlFeature() {}
+
+void TabControlFeature::set_outgoing_message_processor(
+    scoped_ptr<BlimpMessageProcessor> processor) {
+  outgoing_message_processor_ = std::move(processor);
+}
+
+void TabControlFeature::SetSizeAndScale(const gfx::Size& size,
+                                        float device_pixel_ratio) {
+  SizeMessage* size_details;
+  scoped_ptr<BlimpMessage> message = CreateBlimpMessage(&size_details);
+  size_details->set_width(size.width());
+  size_details->set_height(size.height());
+  size_details->set_device_pixel_ratio(device_pixel_ratio);
+
+  // TODO(dtrainor): Don't keep sending size events to the server.  Wait for a
+  // CompletionCallback to return before sending future size updates.
+  outgoing_message_processor_->ProcessMessage(std::move(message),
+                                              net::CompletionCallback());
+}
+
+void TabControlFeature::ProcessMessage(
+    scoped_ptr<BlimpMessage> message,
+    const net::CompletionCallback& callback) {
+  NOTIMPLEMENTED();
+}
+
+}  // namespace blimp
diff --git a/blimp/client/session/tab_control_feature.h b/blimp/client/session/tab_control_feature.h
new file mode 100644
index 0000000..166dec7
--- /dev/null
+++ b/blimp/client/session/tab_control_feature.h
@@ -0,0 +1,46 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BLIMP_CLIENT_SESSION_TAB_CONTROL_FEATURE_H_
+#define BLIMP_CLIENT_SESSION_TAB_CONTROL_FEATURE_H_
+
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "blimp/client/blimp_client_export.h"
+#include "blimp/net/blimp_message_processor.h"
+
+namespace gfx {
+class Size;
+}
+
+namespace blimp {
+
+class BLIMP_CLIENT_EXPORT TabControlFeature : public BlimpMessageProcessor {
+ public:
+  TabControlFeature();
+  ~TabControlFeature() override;
+
+  // Set the BlimpMessageProcessor that will be used to send
+  // BlimpMessage::CONTROL messages to the engine.
+  void set_outgoing_message_processor(
+      scoped_ptr<BlimpMessageProcessor> processor);
+
+  // Pushes the current size and scale information to the engine, which will
+  // affect the web content display area for all tabs.
+  void SetSizeAndScale(const gfx::Size& size, float device_pixel_ratio);
+
+ private:
+  // BlimpMessageProcessor implementation.
+  void ProcessMessage(scoped_ptr<BlimpMessage> message,
+                      const net::CompletionCallback& callback) override;
+
+  // Used to send BlimpMessage::CONTROL messages to the engine.
+  scoped_ptr<BlimpMessageProcessor> outgoing_message_processor_;
+
+  DISALLOW_COPY_AND_ASSIGN(TabControlFeature);
+};
+
+}  // namespace blimp
+
+#endif  // BLIMP_CLIENT_SESSION_TAB_CONTROL_FEATURE_H_
diff --git a/blimp/client/session/tab_control_feature_android.cc b/blimp/client/session/tab_control_feature_android.cc
new file mode 100644
index 0000000..20da386
--- /dev/null
+++ b/blimp/client/session/tab_control_feature_android.cc
@@ -0,0 +1,54 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "blimp/client/session/tab_control_feature_android.h"
+
+#include "blimp/client/session/blimp_client_session_android.h"
+#include "blimp/client/session/tab_control_feature.h"
+#include "jni/TabControlFeature_jni.h"
+#include "ui/gfx/geometry/size.h"
+
+namespace blimp {
+
+static jlong Init(JNIEnv* env,
+                  const JavaParamRef<jobject>& jobj,
+                  const JavaParamRef<jobject>& blimp_client_session) {
+  BlimpClientSession* client_session =
+      BlimpClientSessionAndroid::FromJavaObject(env,
+                                                blimp_client_session.obj());
+
+  return reinterpret_cast<intptr_t>(
+      new TabControlFeatureAndroid(env,
+                                   jobj,
+                                   client_session->GetTabControlFeature()));
+}
+
+// static
+bool TabControlFeatureAndroid::RegisterJni(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+TabControlFeatureAndroid::TabControlFeatureAndroid(
+    JNIEnv* env,
+    const base::android::JavaParamRef<jobject>& jobj,
+    TabControlFeature* tab_control_feature)
+    : tab_control_feature_(tab_control_feature) {
+  java_obj_.Reset(env, jobj);
+}
+
+TabControlFeatureAndroid::~TabControlFeatureAndroid() {}
+
+void TabControlFeatureAndroid::Destroy(JNIEnv* env, jobject jobj) {
+  delete this;
+}
+
+void TabControlFeatureAndroid::OnContentAreaSizeChanged(JNIEnv* env,
+                                                        jobject jobj,
+                                                        jint width,
+                                                        jint height,
+                                                        jfloat dp_to_px) {
+  tab_control_feature_->SetSizeAndScale(gfx::Size(width, height), dp_to_px);
+}
+
+}  // namespace blimp
diff --git a/blimp/client/session/tab_control_feature_android.h b/blimp/client/session/tab_control_feature_android.h
new file mode 100644
index 0000000..81aa6c5
--- /dev/null
+++ b/blimp/client/session/tab_control_feature_android.h
@@ -0,0 +1,44 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BLIMP_CLIENT_SESSION_TAB_CONTROL_FEATURE_ANDROID_H_
+#define BLIMP_CLIENT_SESSION_TAB_CONTROL_FEATURE_ANDROID_H_
+
+#include "base/android/jni_android.h"
+#include "base/macros.h"
+
+namespace blimp {
+
+class TabControlFeature;
+
+class TabControlFeatureAndroid {
+ public:
+  static bool RegisterJni(JNIEnv* env);
+
+  TabControlFeatureAndroid(JNIEnv* env,
+                           const base::android::JavaParamRef<jobject>& jobj,
+                           TabControlFeature* tab_control_feature);
+
+  // Methods called from Java via JNI.
+  void Destroy(JNIEnv* env, jobject jobj);
+  void OnContentAreaSizeChanged(JNIEnv* env,
+                                jobject jobj,
+                                jint width,
+                                jint height,
+                                jfloat dp_to_px);
+
+ private:
+  virtual ~TabControlFeatureAndroid();
+
+  TabControlFeature* tab_control_feature_;
+
+  // Reference to the Java object which owns this class.
+  base::android::ScopedJavaGlobalRef<jobject> java_obj_;
+
+  DISALLOW_COPY_AND_ASSIGN(TabControlFeatureAndroid);
+};
+
+}  // namespace blimp
+
+#endif  // BLIMP_CLIENT_SESSION_TAB_CONTROL_FEATURE_ANDROID_H_
diff --git a/blimp/client/session/tab_control_feature_unittest.cc b/blimp/client/session/tab_control_feature_unittest.cc
new file mode 100644
index 0000000..d53bd97
--- /dev/null
+++ b/blimp/client/session/tab_control_feature_unittest.cc
@@ -0,0 +1,57 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "blimp/client/session/tab_control_feature.h"
+
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "blimp/common/proto/blimp_message.pb.h"
+#include "blimp/common/proto/control.pb.h"
+#include "blimp/common/proto/size.pb.h"
+#include "blimp/net/test_common.h"
+#include "net/base/net_errors.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "ui/gfx/geometry/size.h"
+
+using testing::_;
+
+namespace blimp {
+
+MATCHER_P3(EqualsSizeMessage, width, height, dp_to_px, "") {
+  return arg.control().type() == ControlMessage::SIZE &&
+         arg.control().size().width() == width &&
+         arg.control().size().height() == height &&
+         arg.control().size().device_pixel_ratio() == dp_to_px;
+}
+
+class TabControlFeatureTest : public testing::Test {
+ public:
+  TabControlFeatureTest() : out_processor_(nullptr) {}
+
+  void SetUp() override {
+    out_processor_ = new MockBlimpMessageProcessor();
+    feature_.set_outgoing_message_processor(make_scoped_ptr(out_processor_));
+  }
+
+ protected:
+  // This is a raw pointer to a class that is owned by the ControlFeature.
+  MockBlimpMessageProcessor* out_processor_;
+
+  TabControlFeature feature_;
+};
+
+TEST_F(TabControlFeatureTest, CreatesCorrectSizeMessage) {
+  uint64_t width = 10;
+  uint64_t height = 15;
+  float dp_to_px = 1.23f;
+
+  EXPECT_CALL(
+      *out_processor_,
+      MockableProcessMessage(EqualsSizeMessage(width, height, dp_to_px), _))
+      .Times(1);
+  feature_.SetSizeAndScale(gfx::Size(width, height), 1.23f);
+}
+
+}  // namespace blimp
diff --git a/blimp/common/create_blimp_message.cc b/blimp/common/create_blimp_message.cc
index 6697fe0..e4f953a 100644
--- a/blimp/common/create_blimp_message.cc
+++ b/blimp/common/create_blimp_message.cc
@@ -8,8 +8,10 @@
 #include "base/memory/scoped_ptr.h"
 #include "blimp/common/proto/blimp_message.pb.h"
 #include "blimp/common/proto/compositor.pb.h"
+#include "blimp/common/proto/control.pb.h"
 #include "blimp/common/proto/input.pb.h"
 #include "blimp/common/proto/render_widget.pb.h"
+#include "blimp/common/proto/size.pb.h"
 
 namespace blimp {
 
@@ -62,6 +64,15 @@ scoped_ptr<BlimpMessage> CreateBlimpMessage(
   return output;
 }
 
+scoped_ptr<BlimpMessage> CreateBlimpMessage(SizeMessage** size_message) {
+  DCHECK(size_message);
+  ControlMessage* control_message;
+  scoped_ptr<BlimpMessage> output = CreateBlimpMessage(&control_message);
+  control_message->set_type(ControlMessage::SIZE);
+  *size_message = control_message->mutable_size();
+  return output;
+}
+
 scoped_ptr<BlimpMessage> CreateStartConnectionMessage(
     const std::string& client_token,
     int protocol_version) {
diff --git a/blimp/common/create_blimp_message.h b/blimp/common/create_blimp_message.h
index 22a508f..c6ac4db 100644
--- a/blimp/common/create_blimp_message.h
+++ b/blimp/common/create_blimp_message.h
@@ -18,6 +18,7 @@ class ControlMessage;
 class InputMessage;
 class NavigationMessage;
 class RenderWidgetMessage;
+class SizeMessage;
 class StartConnectionMessage;
 
 // Suite of helper methods to simplify the repetitive task of creating
@@ -50,6 +51,9 @@ BLIMP_COMMON_EXPORT scoped_ptr<BlimpMessage> CreateBlimpMessage(
     RenderWidgetMessage** render_widget_message,
     int target_tab_id);
 
+BLIMP_COMMON_EXPORT scoped_ptr<BlimpMessage> CreateBlimpMessage(
+    SizeMessage** size_message);
+
 BLIMP_COMMON_EXPORT scoped_ptr<BlimpMessage> CreateStartConnectionMessage(
     const std::string& client_token,
     int protocol_version);
diff --git a/blimp/common/create_blimp_message_unittest.cc b/blimp/common/create_blimp_message_unittest.cc
index 8414ed5..0c1760d 100644
--- a/blimp/common/create_blimp_message_unittest.cc
+++ b/blimp/common/create_blimp_message_unittest.cc
@@ -9,6 +9,7 @@
 #include "blimp/common/proto/input.pb.h"
 #include "blimp/common/proto/navigation.pb.h"
 #include "blimp/common/proto/render_widget.pb.h"
+#include "blimp/common/proto/size.pb.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace blimp {
@@ -59,6 +60,15 @@ TEST(CreateBlimpMessageTest, RenderWidgetMessage) {
   EXPECT_EQ(kTabId, message->target_tab_id());
 }
 
+TEST(CreateBlimpMessageTest, SizeMessage) {
+  SizeMessage* details = nullptr;
+  scoped_ptr<BlimpMessage> message = CreateBlimpMessage(&details);
+  EXPECT_NE(nullptr, details);
+  EXPECT_NE(nullptr, message);
+  EXPECT_EQ(ControlMessage::SIZE, message->mutable_control()->type());
+  EXPECT_EQ(details, message->mutable_control()->mutable_size());
+}
+
 TEST(CreateBlimpMessageTest, StartConnectionMessage) {
   const char* client_token = "token";
   const int protocol_version = 1;
diff --git a/blimp/common/proto/control.proto b/blimp/common/proto/control.proto
index 1a909b6..8d29789 100644
--- a/blimp/common/proto/control.proto
+++ b/blimp/common/proto/control.proto
@@ -28,5 +28,6 @@ message ControlMessage {
 
   // Feature-specific messages follow.
   // Only one of these fields may be set per ControlMessage.
-  optional SizeMessage resize = 1000;
+  // TODO(kmarshall): use a 'oneof' union when it's supported in Chromium.
+  optional SizeMessage size = 1000;
 }
diff --git a/blimp/common/proto/size.proto b/blimp/common/proto/size.proto
index f6ba801..fc59b2d 100644
--- a/blimp/common/proto/size.proto
+++ b/blimp/common/proto/size.proto
@@ -13,5 +13,6 @@ package blimp;
 message SizeMessage {
   optional uint64 width = 1;
   optional uint64 height = 2;
+  optional float device_pixel_ratio = 3;
 }
 
diff --git a/blimp/engine/browser/blimp_engine_session.cc b/blimp/engine/browser/blimp_engine_session.cc
index aba826c..aa17d29a 100644
--- a/blimp/engine/browser/blimp_engine_session.cc
+++ b/blimp/engine/browser/blimp_engine_session.cc
@@ -41,6 +41,9 @@ namespace engine {
 namespace {
 
 const int kDummyTabId = 0;
+const float kDefaultScaleFactor = 1.f;
+const int kDefaultDisplayWidth = 800;
+const int kDefaultDisplayHeight = 600;
 
 base::LazyInstance<blimp::NullBlimpMessageProcessor> g_blimp_message_processor =
     LAZY_INSTANCE_INITIALIZER;
@@ -68,6 +71,9 @@ BlimpEngineSession::BlimpEngineSession(
       // TODO(dtrainor, haibinlu): Properly pull these from the BlimpMessageMux.
       render_widget_processor_(g_blimp_message_processor.Pointer(),
                                g_blimp_message_processor.Pointer()) {
+  screen_->UpdateDisplayScaleAndSize(kDefaultScaleFactor,
+                                     gfx::Size(kDefaultDisplayWidth,
+                                               kDefaultDisplayHeight));
   render_widget_processor_.SetDelegate(kDummyTabId, this);
 }
 
@@ -121,9 +127,13 @@ void BlimpEngineSession::CloseWebContents(const int target_tab_id) {
   web_contents_->Close();
 }
 
-void BlimpEngineSession::HandleResize(const gfx::Size& size) {
-  // TODO(dtrainor, haibinlu): Set the proper size on the WebContents/save for
-  // future WebContents objects.
+void BlimpEngineSession::HandleResize(float device_pixel_ratio,
+                                      const gfx::Size& size) {
+  screen_->UpdateDisplayScaleAndSize(device_pixel_ratio, size);
+  if (web_contents_ && web_contents_->GetRenderViewHost() &&
+      web_contents_->GetRenderViewHost()->GetWidget()) {
+    web_contents_->GetRenderViewHost()->GetWidget()->WasResized();
+  }
 }
 
 void BlimpEngineSession::LoadUrl(const int target_tab_id, const GURL& url) {
@@ -198,8 +208,9 @@ void BlimpEngineSession::ProcessMessage(
       case ControlMessage::CLOSE_TAB:
         CloseWebContents(message->target_tab_id());
       case ControlMessage::SIZE:
-        HandleResize(gfx::Size(message->control().resize().width(),
-                               message->control().resize().height()));
+        HandleResize(message->control().size().device_pixel_ratio(),
+                     gfx::Size(message->control().size().width(),
+                               message->control().size().height()));
         break;
       default:
         NOTIMPLEMENTED();
diff --git a/blimp/engine/browser/blimp_engine_session.h b/blimp/engine/browser/blimp_engine_session.h
index e834fe3..61f772b 100644
--- a/blimp/engine/browser/blimp_engine_session.h
+++ b/blimp/engine/browser/blimp_engine_session.h
@@ -74,7 +74,7 @@ class BlimpEngineSession
   // Creates a new WebContents, which will be indexed by |target_tab_id|.
   void CreateWebContents(const int target_tab_id);
   void CloseWebContents(const int target_tab_id);
-  void HandleResize(const gfx::Size& size);
+  void HandleResize(float device_pixel_ratio, const gfx::Size& size);
 
   // NavigationMessage handler methods.
   // Navigates the target tab to the |url|.
diff --git a/blimp/engine/ui/blimp_screen.cc b/blimp/engine/ui/blimp_screen.cc
index 0282967..0e38138 100644
--- a/blimp/engine/ui/blimp_screen.cc
+++ b/blimp/engine/ui/blimp_screen.cc
@@ -10,23 +10,17 @@ namespace engine {
 namespace {
 
 const int64 kDisplayId = 1;
-const float kDefaultScale = 1.0f;
 const int kNumDisplays = 1;
 
 }  // namespace
 
-const int BlimpScreen::kDefaultDisplayWidth = 800;
-const int BlimpScreen::kDefaultDisplayHeight = 600;
-
-BlimpScreen::BlimpScreen() : display_(kDisplayId) {
-  display_.SetScaleAndBounds(
-      kDefaultScale, gfx::Rect(kDefaultDisplayWidth, kDefaultDisplayHeight));
-}
+BlimpScreen::BlimpScreen() : display_(kDisplayId) {}
 
 BlimpScreen::~BlimpScreen() {}
 
-void BlimpScreen::UpdateDisplaySize(const gfx::Size& size) {
-  display_.SetScaleAndBounds(kDefaultScale, gfx::Rect(size));
+void BlimpScreen::UpdateDisplayScaleAndSize(float scale,
+                                            const gfx::Size& size) {
+  display_.SetScaleAndBounds(scale, gfx::Rect(size));
 }
 
 gfx::Point BlimpScreen::GetCursorScreenPoint() {
diff --git a/blimp/engine/ui/blimp_screen.h b/blimp/engine/ui/blimp_screen.h
index 7901780..0e2e550 100644
--- a/blimp/engine/ui/blimp_screen.h
+++ b/blimp/engine/ui/blimp_screen.h
@@ -21,7 +21,7 @@ class BlimpScreen : public gfx::Screen {
   ~BlimpScreen() override;
 
   // Updates the size reported by the primary display.
-  void UpdateDisplaySize(const gfx::Size& size);
+  void UpdateDisplayScaleAndSize(float scale, const gfx::Size& size);
 
   // gfx::Screen implementation.
   gfx::Point GetCursorScreenPoint() override;
@@ -36,9 +36,6 @@ class BlimpScreen : public gfx::Screen {
   void AddObserver(gfx::DisplayObserver* observer) override;
   void RemoveObserver(gfx::DisplayObserver* observer) override;
 
-  static const int kDefaultDisplayWidth;
-  static const int kDefaultDisplayHeight;
-
  private:
   gfx::Display display_;