[Cronet] Fix race in UploadDataStream.attachToRequest.

components/cronet/android/java/src/org/chromium/net/CronetUrlRequest.java

Index: components/cronet/android/java/src/org/chromium/net/CronetUrlRequest.java
diff --git a/components/cronet/android/java/src/org/chromium/net/CronetUrlRequest.java b/components/cronet/android/java/src/org/chromium/net/CronetUrlRequest.java
index e03e97dde1463e8ce594a9b54d2bc6355fd0c5de..3c99d95e85c5e4367bf545015578a827a309af56 100644
--- a/components/cronet/android/java/src/org/chromium/net/CronetUrlRequest.java
+++ b/components/cronet/android/java/src/org/chromium/net/CronetUrlRequest.java
@@ -210,8 +210,7 @@ final class CronetUrlRequest implements UrlRequest {
                         throw new IllegalArgumentException(
                                 "Requests with upload data must have a Content-Type.");
                     }
-                    mStarted = true;

[mef, 2016/03/10 17:10:39]

This was also a problem as 'isDone' is looking at this flag.

[xunjieli, 2016/03/10 17:29:53]

But if start() is called a second time before the runnable is executed, won't
that make the request to be started a second time?

[mef, 2016/03/10 17:44:05]

Ah, excellent point! Done.

-                    mUploadDataStream.attachToRequest(this, mUrlRequestAdapter, new Runnable() {
+                    mUploadDataStream.postTaskToExecutor(new Runnable() {
                         @Override
                         public void run() {
                             synchronized (mUrlRequestAdapterLock) {
@@ -227,19 +226,25 @@ final class CronetUrlRequest implements UrlRequest {
                 destroyRequestAdapter(false);
                 throw e;
             }
-            mStarted = true;
             startInternalLocked();
         }
     }
 
     @GuardedBy("mUrlRequestAdapterLock")
     private void startInternalLocked() {
+        if (mUrlRequestAdapter == 0) {
+            return;
+        }
+        if (mUploadDataStream != null) {
+            mUploadDataStream.attachToRequest(this, mUrlRequestAdapter);

[mef, 2016/03/10 17:10:39]

attach only if request is still valid.

+        }
         if (mDisableCache) {
             nativeDisableCache(mUrlRequestAdapter);
         }
         if (mRequestMetricsAccumulator != null) {
             mRequestMetricsAccumulator.onRequestStarted();
         }
+        mStarted = true;
         nativeStart(mUrlRequestAdapter);
     }