[android] Resize the android_webview if it's 0x0 initially.

android_webview/native/aw_settings.cc

Index: android_webview/native/aw_settings.cc
diff --git a/android_webview/native/aw_settings.cc b/android_webview/native/aw_settings.cc
index 8ab91dd12d6b454c93676997d5fabe40ecb78cb5..81ff07414d6e52172e10e820a6dbf981b28c6451 100644
--- a/android_webview/native/aw_settings.cc
+++ b/android_webview/native/aw_settings.cc
@@ -6,6 +6,8 @@
 
 #include "android_webview/browser/renderer_host/aw_render_view_host_ext.h"
 #include "android_webview/native/aw_contents.h"
+#include "content/public/browser/render_view_host.h"
+#include "content/public/browser/web_contents.h"
 #include "jni/AwSettings_jni.h"
 #include "webkit/glue/webkit_glue.h"
 
@@ -50,8 +52,15 @@ void AwSettings::SetTextZoom(JNIEnv* env, jobject obj, jint text_zoom_percent) {
   UpdateTextZoom();
 }
 
-void AwSettings::SetWebContents(JNIEnv* env, jobject obj, jint web_contents) {
-  Observe(reinterpret_cast<content::WebContents*>(web_contents));
+void AwSettings::SetWebContents(JNIEnv* env, jobject obj, jint jweb_contents) {
+  content::WebContents* web_contents =
+      reinterpret_cast<content::WebContents*>(jweb_contents);
+  Observe(web_contents);
+
+  UpdateRenderViewHostExtSettings();
+  if (web_contents->GetRenderViewHost()) {
+    UpdateRenderViewHostSettings(web_contents->GetRenderViewHost());
+  }
 }
 
 void AwSettings::UpdateInitialPageScale() {
@@ -76,11 +85,37 @@ void AwSettings::UpdateTextZoom() {
   }
 }
 
-void AwSettings::RenderViewCreated(content::RenderViewHost* render_view_host) {
+void AwSettings::UpdatePreferredSizeMode(
+    content::RenderViewHost* render_view_host) {
+  render_view_host->EnablePreferredSizeMode();
+}
+
+void AwSettings::UpdateRenderViewHostExtSettings() {
   UpdateInitialPageScale();
   UpdateTextZoom();
 }
 
+void AwSettings::UpdateRenderViewHostSettings(
+    content::RenderViewHost* render_view_host) {
+  UpdatePreferredSizeMode(render_view_host);
+}
+
+void AwSettings::RenderViewCreated(content::RenderViewHost* render_view_host) {
+  // A single WebContents can normally have 0, 1 or 2 RenderViewHost instances
+  // associated with it.
+  // This is important since there is only one RenderViewHostExt instance per
+  // WebContents (and not one RVHExt per RVH, as you might expect) and updating
+  // settings via RVHExt only ever updates the 'current' RVH.
+  // In android_webview we don't swap out the RVH on cross-site navigations, so
+  // we shouldn't have to deal with the multiple RVH per WebContents case. That
+  // in turn means that the newly created RVH is always the 'current' RVH
+  // (since we only ever go from 0 to 1 RVH instances) and hence the DCHECK.
+  DCHECK(web_contents()->GetRenderViewHost() == render_view_host);
+
+  UpdateRenderViewHostExtSettings();
+  UpdateRenderViewHostSettings(render_view_host);
+}
+
 static jint Init(JNIEnv* env,
                  jobject obj,
                  jint web_contents) {