Readd "immediate" mode

This isn't an exact replacement. The accumulated batches are now flushed at drawContext-entry-point granularity (via the AutoCheckFlush objects) rather than per batch.

TBR=bsalomon@google.com

Review URL: https://codereview.chromium.org/1439533003
diff --git a/src/gpu/GrCaps.cpp b/src/gpu/GrCaps.cpp
index 3331db5..e4f81ab 100644
--- a/src/gpu/GrCaps.cpp
+++ b/src/gpu/GrCaps.cpp
@@ -111,7 +111,8 @@
     memset(fConfigRenderSupport, 0, sizeof(fConfigRenderSupport));
     memset(fConfigTextureSupport, 0, sizeof(fConfigTextureSupport));
 
-    fSupressPrints = options.fSuppressPrints;
+    fSuppressPrints = options.fSuppressPrints;
+    fImmediateFlush = options.fImmediateMode;
     fDrawPathMasksToCompressedTextureSupport = options.fDrawPathToCompressedTexture;
     fGeometryBufferMapThreshold = options.fGeometryBufferMapThreshold;
     fUseDrawInsteadOfPartialRenderTargetWrite = options.fUseDrawInsteadOfPartialRenderTargetWrite;