Refactor read and write buffers.

Eliminates SkFlattenable{Read,Write}Buffer, promoting SkOrdered{Read,Write}Buffer
a step each in the hierarchy.

What used to be this:

SkFlattenableWriteBuffer -> SkOrderedWriteBuffer
SkFlattenableReadBuffer  -> SkOrderedReadBuffer
SkFlattenableReadBuffer  -> SkValidatingReadBuffer

is now

SkWriteBuffer
SkReadBuffer -> SkValidatingReadBuffer

Benefits:
  - code is simpler, names are less wordy
  - the generic SkFlattenableFooBuffer code in SkPaint was incorrect; removed
  - write buffers are completely devirtualized, important for record speed

This refactoring was mostly mechanical.  You aren't going to find anything
interesting in files with less than 10 lines changed.

BUG=skia:
R=reed@google.com, scroggo@google.com, djsollen@google.com, mtklein@google.com

Author: mtklein@chromium.org

Review URL: https://codereview.chromium.org/134163010

git-svn-id: http://skia.googlecode.com/svn/trunk@13245 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/effects/SkArithmeticMode.cpp b/src/effects/SkArithmeticMode.cpp
index 93d708a..052b065 100644
--- a/src/effects/SkArithmeticMode.cpp
+++ b/src/effects/SkArithmeticMode.cpp
@@ -7,7 +7,8 @@
 
 #include "SkArithmeticMode.h"
 #include "SkColorPriv.h"
-#include "SkFlattenableBuffers.h"
+#include "SkReadBuffer.h"
+#include "SkWriteBuffer.h"
 #include "SkString.h"
 #include "SkUnPreMultiply.h"
 #if SK_SUPPORT_GPU
@@ -40,14 +41,14 @@
 #endif
 
 private:
-    SkArithmeticMode_scalar(SkFlattenableReadBuffer& buffer) : INHERITED(buffer) {
+    SkArithmeticMode_scalar(SkReadBuffer& buffer) : INHERITED(buffer) {
         fK[0] = buffer.readScalar();
         fK[1] = buffer.readScalar();
         fK[2] = buffer.readScalar();
         fK[3] = buffer.readScalar();
     }
 
-    virtual void flatten(SkFlattenableWriteBuffer& buffer) const SK_OVERRIDE {
+    virtual void flatten(SkWriteBuffer& buffer) const SK_OVERRIDE {
         INHERITED::flatten(buffer);
         buffer.writeScalar(fK[0]);
         buffer.writeScalar(fK[1]);