Remove most native WebContents references from Java

chrome/browser/android/tab_android.cc

 // Copyright (c) 2012 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 "chrome/browser/android/tab_android.h"
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_array.h"
 #include "base/android/jni_string.h"
 #include "base/debug/trace_event.h"
@@ skipping 272 matching lines @@
           Java_Tab_getNativeInfoBarContainer(
               env,
               weak_java_tab_.get(env).obj()));
   InfoBarService* new_infobar_service =
       new_contents ? InfoBarService::FromWebContents(new_contents) : NULL;
   infobar_container->ChangeInfoBarManager(new_infobar_service);
 
   Java_Tab_swapWebContents(
       env,
       weak_java_tab_.get(env).obj(),
-      reinterpret_cast<intptr_t>(new_contents),
+      new_contents->GetJavaWebContents().obj(),
       did_start_load,
       did_finish_load);
 }
 
 void TabAndroid::DefaultSearchProviderChanged() {
   // TODO(kmadhusu): Move this function definition to a common place and update
   // BrowserInstantController::DefaultSearchProviderChanged to use the same.
   if (!web_contents())
     return;
 
@@ skipping 455 matching lines @@
   //   s^{n+1} / s^{n} = 2100 / 2000
   //   s = 1.05
   //   s^b = 60000
   //   b = ln(60000) / ln(1.05) ~= 225
   UMA_HISTOGRAM_CUSTOM_TIMES("Startup.FirstCommitNavigationTime",
       base::Time::Now() - chrome::android::GetMainEntryPointTime(),
       base::TimeDelta::FromMilliseconds(1),
       base::TimeDelta::FromMinutes(1),
       225);
 }