Convert geometry shaders to operate in Skia device space

Defers the transformation to normalized window coordinates until after
the geometry shader. Merges vertex and a geometry shader builders into
a single compilation unit with a common base class.  Updates CCPR
geometry shaders accordingly.

Bug: skia:
Change-Id: If93c90e978b1fdc7120febd05cfb05810fd496b5
Reviewed-on: https://skia-review.googlesource.com/62980
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
diff --git a/samplecode/SampleCCPRGeometry.cpp b/samplecode/SampleCCPRGeometry.cpp
index aa1fb8b..8633398 100644
--- a/samplecode/SampleCCPRGeometry.cpp
+++ b/samplecode/SampleCCPRGeometry.cpp
@@ -70,9 +70,9 @@
 
     SkPoint fPoints[4] = {
         {100.05f, 100.05f},
-        {100.05f, 300.95f},
+        {400.75f, 100.05f},
         {400.75f, 300.95f},
-        {400.75f, 100.05f}
+        {100.05f, 300.95f}
     };
 
     SkTArray<SkPoint>   fGpuPoints;