Add WebViewChromiumAwInit class.

This is patch 1/3 to move everything protected under
WebViewChromiumFactoryProvider.mLock into WebViewChromiumAwInit.
Patches:
1. Create WebViewChromiumAwInit and some methods for down-stream use.
2.  Update the down-stream glue-layer to point to
WebViewChromiumAwInit methods.
3. Move code from WebViewChromiumFactoryProvider to
WebViewChromiumAwInit.

Bug: 807332
Change-Id: I346dc325f36f83a3bd20064617bd43aca9f48423
Reviewed-on: https://chromium-review.googlesource.com/895942
Commit-Queue: Gustav Sennton <gsennton@chromium.org>
Reviewed-by: Bo <boliu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#534041}

android_webview/glue/BUILD.gn

@@ -49,6 +49,7 @@ android_library("glue") {
     "java/src/com/android/webview/chromium/WebIconDatabaseAdapter.java",
     "java/src/com/android/webview/chromium/WebMessagePortAdapter.java",
     "java/src/com/android/webview/chromium/WebStorageAdapter.java",
+    "java/src/com/android/webview/chromium/WebViewChromiumAwInit.java",
     "java/src/com/android/webview/chromium/WebViewChromiumFactoryProvider.java",
     "java/src/com/android/webview/chromium/WebViewChromiumFactoryProviderForO.java",
     "java/src/com/android/webview/chromium/WebViewChromiumFactoryProviderForOMR1.java",

android_webview/glue/java/src/com/android/webview/chromium/WebViewChromiumAwInit.java

+// Copyright 2018 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 com.android.webview.chromium;
+
+import org.chromium.android_webview.AwTracingController;
+
+class WebViewChromiumAwInit {
+    private final WebViewChromiumFactoryProvider mFactory;
+
+    WebViewChromiumAwInit(WebViewChromiumFactoryProvider factory) {
+        mFactory = factory;
+        // Do not make calls into 'factory' in this ctor - this ctor is called from the
+        // WebViewChromiumFactoryProvider ctor, so 'factory' is not properly initialized yet.
+    }
+
+    // Allows down-stream to override this.
+    protected void startChromiumLocked() {}
+
+    AwTracingController getTracingControllerOnUiThread() {
+        synchronized (mFactory.mLock) {
+            mFactory.ensureChromiumStartedLocked(true);
+            return mFactory.getBrowserContextOnUiThread().getTracingController();
+        }
+    }
+}

android_webview/glue/java/src/com/android/webview/chromium/WebViewChromiumFactoryProvider.java

@@ -124,6 +124,12 @@ public class WebViewChromiumFactoryProvider implements WebViewFactoryProvider {
         mRunQueue.addTask(task);
     }
 
+    /**
+     * Class that takes care of chromium lazy initialization.
+     * This is package-public so that a downstream subclass can access it.
+     */
+    /* package */ WebViewChromiumAwInit mAwInit;
+
     // Guards accees to the other members, and is notifyAll() signalled on the UI thread
     // when the chromium process has been started.
     // This member is not private only because the downstream subclass needs to access it,
@@ -178,8 +184,14 @@ public class WebViewChromiumFactoryProvider implements WebViewFactoryProvider {
         initialize(delegate);
     }
 
+    // Protected to allow downstream to override.
+    protected WebViewChromiumAwInit createAwInit(WebViewChromiumFactoryProvider provider) {
+        return new WebViewChromiumAwInit(provider);
+    }
+
     @TargetApi(Build.VERSION_CODES.N) // For getSystemService() and isUserUnlocked().
     private void initialize(WebViewDelegate webViewDelegate) {
+        mAwInit = createAwInit(this);
         mWebViewDelegate = webViewDelegate;
         Context ctx = mWebViewDelegate.getApplication().getApplicationContext();
 
@@ -368,6 +380,9 @@ public class WebViewChromiumFactoryProvider implements WebViewFactoryProvider {
     private static final int DIR_RESOURCE_PAKS_ANDROID = 3003;
 
     protected void startChromiumLocked() {
+        // TODO(gsennton): remove this when down-stream is up-to-date:
+        // Call into the AwInit to allow down-stream to override startChromiumLocked
+        mAwInit.startChromiumLocked();
         assert Thread.holdsLock(mLock) && ThreadUtils.runningOnUiThread();
 
         // The post-condition of this method is everything is ready, so notify now to cover all