Add support for using alternative backends (like DirectX) when creating a GrGpu.

src/gpu/GrGpuFactory.cpp

Index: src/gpu/GrGpuFactory.cpp
diff --git a/src/gpu/GrGpuFactory.cpp b/src/gpu/GrGpuFactory.cpp
index 4b09c14e5182ae9e299c073403f5835b3537cec1..9dd9e5eb4244c9a69eee0403a1ca0d99b2e5624f 100644
--- a/src/gpu/GrGpuFactory.cpp
+++ b/src/gpu/GrGpuFactory.cpp
@@ -7,37 +7,44 @@
  */
 
 
-#include "GrTypes.h"
+#include "GrGpuFactory.h"
 
 #include "gl/GrGLConfig.h"
 
 #include "GrGpu.h"
 #include "gl/GrGLGpu.h"
 
-GrGpu* GrGpu::Create(GrBackend backend, GrBackendContext backendContext, GrContext* context) {
-
+static GrGpu* GLGpuCreate(GrBackendContext backendContext, GrContext* context) {

[bsalomon, 2015/03/25 14:11:54]

gl_cpu_create (static_functions_use_hacker_naming)

[egdaniel, 2015/03/25 16:17:17]

Done.

     const GrGLInterface* glInterface = NULL;
     SkAutoTUnref<const GrGLInterface> glInterfaceUnref;
 
-    if (kOpenGL_GrBackend == backend) {
-        glInterface = reinterpret_cast<const GrGLInterface*>(backendContext);
-        if (NULL == glInterface) {
-            glInterface = GrGLDefaultInterface();
-            // By calling GrGLDefaultInterface we've taken a ref on the
-            // returned object. We only want to hold that ref until after
-            // the GrGpu is constructed and has taken ownership.
-            glInterfaceUnref.reset(glInterface);
-        }
-        if (NULL == glInterface) {
+    glInterface = reinterpret_cast<const GrGLInterface*>(backendContext);
+    if (NULL == glInterface) {
+        glInterface = GrGLDefaultInterface();
+        // By calling GrGLDefaultInterface we've taken a ref on the
+        // returned object. We only want to hold that ref until after
+        // the GrGpu is constructed and has taken ownership.
+        glInterfaceUnref.reset(glInterface);
+    }
+    if (NULL == glInterface) {
 #ifdef SK_DEBUG
-            SkDebugf("No GL interface provided!\n");
+        SkDebugf("No GL interface provided!\n");
 #endif
-            return NULL;
-        }
-        GrGLContext ctx(glInterface);
-        if (ctx.isInitialized()) {
-            return SkNEW_ARGS(GrGLGpu, (ctx, context));
-        }
+        return NULL;
+    }
+    GrGLContext ctx(glInterface);
+    if (ctx.isInitialized()) {
+        return SkNEW_ARGS(GrGLGpu, (ctx, context));
     }
     return NULL;
 }
+
+static CreateGpuProc gGpuFactories[4] = {GLGpuCreate, NULL, NULL, NULL};
+
+GrGpuFactoryRegistrar::GrGpuFactoryRegistrar(int i, CreateGpuProc proc) {

[bsalomon, 2015/03/25 14:11:54]

Seems a bit weird to have a fixed sized array. Why not var-length? Also, should
we have a mutex around insertion and access? Not worried about perf here.

[robertphillips, 2015/03/25 16:01:02]

I suggest we keep it simple for this go round and expand the functionality if we
need it in the future.

[egdaniel, 2015/03/25 16:17:17]

Agree with Rob on the simple approach for now. Also if we keep this version for
now, we shouldn't need any mutexes.

+    gGpuFactories[i] = proc;
+}
+
+GrGpu* GrGpu::Create(GrBackend backend, GrBackendContext backendContext, GrContext* context) {

[robertphillips, 2015/03/25 13:58:24]

SkAssert(backend < kMaxNumBackends); ?

[egdaniel, 2015/03/25 16:17:17]

Done.

+    return (gGpuFactories[backend])(backendContext, context);
+}