Revert "draw vertices: put SkVM implementation behind a flag"

This reverts commit 2efda3ad1699e0590aa52c090ce02c82417da801.

Reason for revert: Doesn't pass tests on SkVM bots.

Original change's description:
> draw vertices: put SkVM implementation behind a flag
>
> Change-Id: I8bcaad6169d5e243b48984657347efed7063b654
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/433496
> Commit-Queue: Herb Derby <herb@google.com>
> Reviewed-by: Mike Reed <reed@google.com>

TBR=herb@google.com,reed@google.com,skcq-be@skia-corp.google.com.iam.gserviceaccount.com

Change-Id: Id76791621398481b3af3acf82e459be5263caba3
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/433676
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Herb Derby <herb@google.com>
diff --git a/src/core/SkDraw_vertices.cpp b/src/core/SkDraw_vertices.cpp
index 0c564e4..19d6101 100644
--- a/src/core/SkDraw_vertices.cpp
+++ b/src/core/SkDraw_vertices.cpp
@@ -23,8 +23,6 @@
 #include "src/shaders/SkComposeShader.h"
 #include "src/shaders/SkShaderBase.h"
 
-extern bool gUseSkVMBlitter;
-
 struct Matrix43 {
     float fMat[12];    // column major
 
@@ -308,16 +306,27 @@
 
     VertState       state(vertexCount, indices, indexCount);
     VertState::Proc vertProc = state.chooseProc(info.mode());
+    // No colors are changing and no texture coordinates are changing, so no updates between
+    // triangles are needed. Use SkVM to blit the triangles.
+    if (!colors && (!texCoords || texCoords == positions)) {
+        if (auto blitter = SkVMBlitter::Make(
+                fDst, paint, *fMatrixProvider, outerAlloc, this->fRC->clipShader())) {
+            while (vertProc(&state)) {
+                fill_triangle(state, blitter, *fRC, dev2, dev3);
+            }
+            return;
+        }
+    }
+
+    /*  We need to know if we have perspective or not, so we can know what stage(s) we will need,
+        and how to prep our "uniforms" before each triangle in the tricolorshader.
+
+        We could just check the matrix on each triangle to decide, but we have to be sure to always
+        make the same decision, since we create 1 or 2 stages only once for the entire patch.
+
+        To be safe, we just make that determination here, and pass it into the tricolorshader.
+     */
     SkMatrix ctm = fMatrixProvider->localToDevice();
-    if (!gUseSkVMBlitter) {
-    // We need to know if we have perspective or not, so we can know what stage(s) we will need,
-    // and how to prep our "uniforms" before each triangle in the tricolorshader.
-    //
-    // We could just check the matrix on each triangle to decide, but we have to be sure to
-    // always make the same decision, since we create 1 or 2 stages only once for the entire
-    // patch.
-    //
-    // To be safe, we just make that determination here, and pass it into the tricolorshader.
     const bool usePerspective = ctm.hasPerspective();
 
     SkTriColorShader* triShader = nullptr;
@@ -393,7 +402,6 @@
                 }
             }
         }
-        return;
     } else {
         // must rebuild pipeline for each triangle, to pass in the computed ctm
         while (vertProc(&state)) {
@@ -414,31 +422,11 @@
                 matrixProvider = preConcatMatrixProvider.init(*matrixProvider, localM);
             }
 
-            // TODO: we should make it so that if this fails, then it falls through to SkVM
-            //  drawing.
             if (auto blitter = SkCreateRasterPipelineBlitter(
                     fDst, shaderPaint, *matrixProvider, &innerAlloc, this->fRC->clipShader())) {
                 fill_triangle(state, blitter, *fRC, dev2, dev3);
             }
         }
-        return;
-    }
-    }
-
-    {
-        // No colors are changing and no texture coordinates are changing, so no updates between
-        // triangles are needed. Use SkVM to blit the triangles.
-        if (!colors) {
-            if (!texCoords || texCoords == positions) {
-                if (auto blitter = SkVMBlitter::Make(
-                        fDst, paint, *fMatrixProvider, outerAlloc, this->fRC->clipShader())) {
-                    while (vertProc(&state)) {
-                        fill_triangle(state, blitter, *fRC, dev2, dev3);
-                    }
-                    return;
-                }
-            }
-        }
     }
 }