Fix a pair of Cronet upload bugs and add tests.

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

Index: components/cronet/android/java/src/org/chromium/net/ChromiumUrlRequest.java
diff --git a/components/cronet/android/java/src/org/chromium/net/ChromiumUrlRequest.java b/components/cronet/android/java/src/org/chromium/net/ChromiumUrlRequest.java
index 228682f3e65130201af8af6117a5b7737940285e..ccbf06394c3a92e27f1b73644952bfe448b818d0 100644
--- a/components/cronet/android/java/src/org/chromium/net/ChromiumUrlRequest.java
+++ b/components/cronet/android/java/src/org/chromium/net/ChromiumUrlRequest.java
@@ -319,19 +319,6 @@ public class ChromiumUrlRequest implements HttpUrlRequest {
 
             mStarted = true;
 
-            String method = mMethod;
-            if (method == null &&
-                    ((mUploadData != null && mUploadData.length > 0) ||
-                      mUploadChannel != null || mChunkedUpload)) {
-                // Default to POST if there is data to upload but no method was
-                // specified.
-                method = "POST";
-            }
-
-            if (method != null) {
-                nativeSetMethod(mUrlRequestAdapter, method);
-            }
-
             if (mHeaders != null && !mHeaders.isEmpty()) {
                 for (Entry<String, String> entry : mHeaders.entrySet()) {
                     nativeAddHeader(mUrlRequestAdapter, entry.getKey(),
@@ -358,6 +345,13 @@ public class ChromiumUrlRequest implements HttpUrlRequest {
                                           mUploadContentType);
             }
 
+            // Note:  The above functions to set the upload body also set the
+            // method to POST, behind the scenes, so if mMethod is null but
+            // there's an upload body, the method will default to POST.
+            if (mMethod != null) {
+                nativeSetMethod(mUrlRequestAdapter, mMethod);
+            }
+
             nativeStart(mUrlRequestAdapter);
           }
     }