customtabs: Don't create an extra child process when one is already there.

chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabActivity.java

Index: chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabActivity.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabActivity.java b/chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabActivity.java
index c53db52aee1f7bb72474ba345467a88e665a49d0..0d9ae69eeab1ff4ac2efff9b1169a487acb8c90f 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabActivity.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabActivity.java
@@ -93,6 +93,7 @@ public class CustomTabActivity extends ChromeActivity {
     private boolean mRecordedStartupUma;
     private boolean mHasCreatedTabEarly;
     private boolean mIsInitialStart = true;
+    private boolean mHasPrerender;
     private CustomTabObserver mTabObserver;
 
     private String mPrerenderedUrl;
@@ -212,9 +213,9 @@ public class CustomTabActivity extends ChromeActivity {
         mIntentDataProvider = new CustomTabIntentDataProvider(getIntent(), this);
         mSession = mIntentDataProvider.getSession();
         supportRequestWindowFeature(Window.FEATURE_ACTION_MODE_OVERLAY);
-        boolean prerendered = !TextUtils.isEmpty(
+        mHasPrerender = !TextUtils.isEmpty(
                 CustomTabsConnection.getInstance(getApplication()).getPrerenderedUrl(mSession));
-        if (CustomTabsConnection.hasWarmUpBeenFinished(getApplication()) && !prerendered) {
+        if (CustomTabsConnection.hasWarmUpBeenFinished(getApplication()) && !mHasPrerender) {
             mMainTab = createMainTab();
             loadUrlInTab(mMainTab, new LoadUrlParams(getUrlToLoad()),
                     IntentHandler.getTimestampFromIntent(getIntent()));
@@ -223,6 +224,11 @@ public class CustomTabActivity extends ChromeActivity {
     }
 
     @Override
+    public boolean shouldAllocateChildConnection() {
+        return !mHasCreatedTabEarly && !mHasPrerender;
+    }
+
+    @Override
     public void postInflationStartup() {
         super.postInflationStartup();
         setTabModelSelector(new TabModelSelectorImpl(this,