aw: Use async upload by default

android_webview/lib/main/aw_main_delegate.cc

Index: android_webview/lib/main/aw_main_delegate.cc
diff --git a/android_webview/lib/main/aw_main_delegate.cc b/android_webview/lib/main/aw_main_delegate.cc
index 371a45e30f918d5e6803ac0e0a17c7e8138d4922..f6ecd072fe7010ff81828da5ddccbba14171fb9f 100644
--- a/android_webview/lib/main/aw_main_delegate.cc
+++ b/android_webview/lib/main/aw_main_delegate.cc
@@ -53,6 +53,7 @@ bool AwMainDelegate::BasicStartupComplete(int* exit_code) {
   CommandLine* cl = CommandLine::ForCurrentProcess();
   bool zero_copy_disabled_by_switch = cl->HasSwitch(switches::kDisableZeroCopy);
   bool use_zero_copy = !zero_copy_disabled_by_switch &&
+                       cl->HasSwitch(switches::kEnableZeroCopy) &&

[hush (inactive), 2014/08/11 17:12:49]

we have both kEnableZeroCopy and kDisableZeroCopy in content_switches.cc

This seems redundant, and confusing if you pass both options in the command
line.

But it seems both options are used in content/ folder. What's the point?
Can we keep kDisableZeroCopy and remove kEnableZeroCopy?

[boliu, 2014/08/11 17:15:06]

The rule is always disable trumps enable.
I don't actually know. I'd guess it probably has something to do with running
experiments and easily flipping the default case.
Ehh, follow up clean up

[hush (inactive), 2014/08/11 17:38:51]

Seems like content owners added it on purpose in this CL:
https://codereview.chromium.org/236313006
On 2014/08/11 17:15:06, boliu wrote:

                        gpu_memory_buffer_factory_.get()->Initialize();
 
   if (use_zero_copy) {