Change ACCELERATED_COMPOSITING blacklist to GPU_COMPOSITING.

content/public/common/content_switches.cc

Index: content/public/common/content_switches.cc
diff --git a/content/public/common/content_switches.cc b/content/public/common/content_switches.cc
index 0695bdd50a32b2c8ffafab03df84bf8ed3e534d5..8aa40e5ffe7e32e002304c268837ca7e78fea2b7 100644
--- a/content/public/common/content_switches.cc
+++ b/content/public/common/content_switches.cc
@@ -38,9 +38,9 @@ const char kAuditAllHandles[]               = "enable-handle-auditing-all";
 // is terminated.
 const char kAuditHandles[]                  = "enable-handle-auditing";
 
-// Blacklist the GPU for accelerated compositing.
-const char kBlacklistAcceleratedCompositing[] =
-    "blacklist-accelerated-compositing";
+// Blacklist the GPU for GPU compositing, to force software compositing.
+const char kBlacklistGpuCompositing[] =
+    "blacklist-gpu-compositing";

[piman, 2014/04/16 17:56:13]

What's the use of that over --disable-gpu?

[danakj, 2014/04/16 18:07:43]

I don't know I was going to ask about this. It seemed like this was meant for
testing as if the card was blacklisted somehow. At first I removed it but I'm
not sure if people use it:

1. --disable-gpu causes GpuDataManagerImplPrivate::DisableHardwareAcceleration()
to happen in the constructor.
2. --disable-gpu then sets card_blacklisted_ = true
3. --disable-gpu then puts GPU_COMPOSITING into the blacklisted_features_

Later, GpuDataManagerImplPrivate::Initialize happens which goes to
InitializeImpl:
1. InitializeImpl calls UpdateGpuInfo which calls UpdateGpuInfoHelper
2. UpdateGpuInfoHelper gets a new |features| set from
gpu_blacklist_->MakeDecision
3. This |features| is given to UpdateBlacklistedFeatures 
4. The |features| replaces blacklisted_features_

At this point --disable-gpu has done nothing except mark card_blacklisted =
true.

5. If card_blacklisted_ or kBlacklistGpuCompositing, we add GPU_COMPOSITING back
to blacklisted_features.

So:
- Why does --disable-gpu bother doing anything except set card_blacklisted_ ?
- I don't think this flag is very useful, but then the same argument for
kBlacklistWebGL. Should I remove them both as another CL together?

 
 // Blacklist the GPU for WebGL.
 const char kBlacklistWebGL[]                = "blacklist-webgl";