Remove non-impl-side painting as an option for blink.

content/browser/renderer_host/render_process_host_impl.cc

Index: content/browser/renderer_host/render_process_host_impl.cc
diff --git a/content/browser/renderer_host/render_process_host_impl.cc b/content/browser/renderer_host/render_process_host_impl.cc
index b96b4bf6ed446b70845edc5c3ba44342fe6f2f6b..8bf03f8fff7582ad1f85957b99122f9f00afadb5 100644
--- a/content/browser/renderer_host/render_process_host_impl.cc
+++ b/content/browser/renderer_host/render_process_host_impl.cc
@@ -1112,13 +1112,9 @@ static void AppendCompositorCommandLineFlags(base::CommandLine* command_line) {
   if (IsDelegatedRendererEnabled())
     command_line->AppendSwitch(switches::kEnableDelegatedRenderer);
 
-  if (IsImplSidePaintingEnabled()) {
-    command_line->AppendSwitchASCII(
-        switches::kNumRasterThreads,
-        base::IntToString(NumberOfRendererRasterThreads()));
-  } else {
-    command_line->AppendSwitch(switches::kDisableImplSidePainting);
-  }
+  command_line->AppendSwitchASCII(
+      switches::kNumRasterThreads,
+      base::IntToString(NumberOfRendererRasterThreads()));
 
   if (IsGpuRasterizationEnabled())
     command_line->AppendSwitch(switches::kEnableGpuRasterization);
@@ -1261,7 +1257,6 @@ void RenderProcessHostImpl::PropagateBrowserCommandLineToRenderer(
     switches::kEnableBrowserSideNavigation,
     switches::kEnableCompositorAnimationTimelines,
     switches::kEnableCredentialManagerAPI,
-    switches::kEnableDeferredImageDecoding,
     switches::kEnableDelayAgnosticAec,
     switches::kEnableDisplayList2dCanvas,
     switches::kEnableDistanceFieldText,
@@ -1414,11 +1409,6 @@ void RenderProcessHostImpl::PropagateBrowserCommandLineToRenderer(
     renderer_cmd->AppendSwitch(switches::kDisableDatabases);
   }
 
-  // Enforce the extra command line flags for impl-side painting.
-  if (IsImplSidePaintingEnabled() &&
-      !browser_cmd.HasSwitch(switches::kEnableDeferredImageDecoding))
-    renderer_cmd->AppendSwitch(switches::kEnableDeferredImageDecoding);
-
   // Add kWaitForDebugger to let renderer process wait for a debugger.
   if (browser_cmd.HasSwitch(switches::kWaitForDebuggerChildren)) {
     // Look to pass-on the kWaitForDebugger flag.