[Cronet] Fix CronetFixedModeOutputStream to not write more bytes than specified

components/cronet/android/test/javatests/src/org/chromium/net/urlconnection/CronetFixedModeOutputStreamTest.java

Index: components/cronet/android/test/javatests/src/org/chromium/net/urlconnection/CronetFixedModeOutputStreamTest.java
diff --git a/components/cronet/android/test/javatests/src/org/chromium/net/urlconnection/CronetFixedModeOutputStreamTest.java b/components/cronet/android/test/javatests/src/org/chromium/net/urlconnection/CronetFixedModeOutputStreamTest.java
index 3dddc7397f85d78d7a221cbebae90383be18e211..af77e377a4c035546033173e938ad292f746a970 100644
--- a/components/cronet/android/test/javatests/src/org/chromium/net/urlconnection/CronetFixedModeOutputStreamTest.java
+++ b/components/cronet/android/test/javatests/src/org/chromium/net/urlconnection/CronetFixedModeOutputStreamTest.java
@@ -275,14 +275,14 @@ public class CronetFixedModeOutputStreamTest extends CronetTestBase {
     @SmallTest
     @Feature({"Cronet"})
     @OnlyRunCronetHttpURLConnection
-    public void testLargeDataMoreThanNativeBufferSize()
-            throws Exception {
+    public void testJavaBufferSizeLargerThanNativeBufferSize() throws Exception {
         // Set an internal buffer of size larger than the buffer size used
         // in network stack internally.
         // Normal stream uses 16384, QUIC uses 14520, and SPDY uses 16384.
-        CronetFixedModeOutputStream.setDefaultBufferLengthForTesting(17384);
+        CronetFixedModeOutputStream.setDefaultBufferLengthForTesting(18384);

[pauljensen, 2016/06/14 12:50:31]

why the buffer size change?

[xunjieli, 2016/06/14 13:12:48]

That's a very good question. (I should have commented on this). The size is
changed so this test can catch the regression.

The regression happens when the last mBuffer has more bytes than the what the
native buffer size can hold. In this case, the last mBuffer will contain
1,800,000 % 18384 = 16752 > 16384 (native buffer size). The previous buffer size
wasn't fully exercising the code.

         testFixedLengthStreamingModeLargeDataWriteOneByte();
         testFixedLengthStreamingModeLargeData();
+        testOneMassiveWrite();

[pauljensen, 2016/06/14 12:50:31]

can you add a comment about what this call does?  I assume it tests a large
upload.
how does this compile?  I don't see an import of this function.

[xunjieli, 2016/06/14 13:12:48]

It's a test method. I've added a comment.

     }
 
     @SmallTest