Revert of Command Buffer: read pixels into pixel pack buffer

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index d6c71c0d43d8b42accf33c4725d10a222c5ccd1c..e8bbe5885459434f3dff96c195f981ae1b6ee30d 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -9174,61 +9174,24 @@
     return error::kNoError;
   }
   typedef cmds::ReadPixels::Result Result;
-  uint32 pixels_size = 0;
-  if (c.pixels_shm_id == 0) {
-    PixelStoreParams params = state_.GetPackParams();
-    if (!GLES2Util::ComputeImageDataSizesES3(width, height, 1, format, type,
-        params, &pixels_size, nullptr, nullptr, nullptr)) {
-      return error::kOutOfBounds;
-    }
-  } else {
-    // When reading into client buffer, we actually set pack parameters to 0
-    // (except for alignment) before calling glReadPixels. This makes sure we
-    // only send back meaningful pixel data to the command buffer client side,
-    // and the client side will take the responsibility to take the pixels and
-    // write to the client buffer according to the full ES3 pack parameters.
-    if (!GLES2Util::ComputeImageDataSizes(width, height, 1, format, type,
-        state_.pack_alignment, &pixels_size, nullptr, nullptr)) {
-      return error::kOutOfBounds;
-    }
-  }
-
-  void* pixels = nullptr;
-  Buffer* buffer = state_.bound_pixel_pack_buffer.get();
-  if (c.pixels_shm_id == 0) {
-    if (buffer) {
-      if (buffer->GetMappedRange()) {
-        LOCAL_SET_GL_ERROR(GL_INVALID_OPERATION, "glReadPixels",
-            "pixel pack buffer should not be mapped to client memory");
-        return error::kNoError;
-      }
-      uint32 size = 0;
-      if (!SafeAddUint32(pixels_size, c.pixels_shm_offset, &size)) {
-        LOCAL_SET_GL_ERROR(
-            GL_INVALID_VALUE, "glReadPixels", "size + offset overflow");
-        return error::kNoError;
-      }
-      if (static_cast<uint32>(buffer->size()) < size) {
-        LOCAL_SET_GL_ERROR(GL_INVALID_OPERATION, "glReadPixels",
-            "pixel pack buffer is not large enough");
-        return error::kNoError;
-      }
-      pixels = reinterpret_cast<void *>(c.pixels_shm_offset);
-    } else {
-      return error::kInvalidArguments;
-    }
-  } else {
-    if (buffer) {
-      return error::kInvalidArguments;
-    } else {
-      pixels = GetSharedMemoryAs<void*>(
-          c.pixels_shm_id, c.pixels_shm_offset, pixels_size);
-      if (!pixels) {
-        return error::kOutOfBounds;
-      }
-    }
-  }
-
+  uint32 pixels_size;
+  if (state_.bound_pixel_pack_buffer.get()) {
+    // TODO(zmo): Need to handle the case of reading into a PIXEL_PACK_BUFFER
+    // in ES3, including more pack parameters. For now, generate a GL error.
+    LOCAL_SET_GL_ERROR(GL_INVALID_OPERATION, "glReadPixels",
+                       "ReadPixels to a pixel pack buffer isn't implemented");
+    return error::kNoError;
+  }
+  if (!GLES2Util::ComputeImageDataSizes(
+      width, height, 1, format, type, state_.pack_alignment, &pixels_size,
+      NULL, NULL)) {
+    return error::kOutOfBounds;
+  }
+  void* pixels = GetSharedMemoryAs<void*>(
+      c.pixels_shm_id, c.pixels_shm_offset, pixels_size);
+  if (!pixels) {
+    return error::kOutOfBounds;
+  }
   Result* result = NULL;
   if (c.result_shm_id != 0) {
     result = GetSharedMemoryAs<Result*>(
@@ -9364,13 +9327,6 @@
   ScopedResolvedFrameBufferBinder binder(this, false, true);
 
   if (x < 0 || y < 0 || max_x > max_size.width() || max_y > max_size.height()) {
-    // TODO(yunchao): need to handle the out-of-bounds case for reading pixels
-    // into PIXEL_PACK buffer.
-    if (c.pixels_shm_id == 0) {
-      LOCAL_SET_GL_ERROR(GL_INVALID_OPERATION, "glReadPixels",
-          "read pixels out of bounds into PIXEL_PACK buffer");
-      return error::kNoError;
-    }
     // The user requested an out of range area. Get the results 1 line
     // at a time.
     uint32 temp_size;
@@ -9446,14 +9402,12 @@
     }
     glReadPixels(x, y, width, height, format, type, pixels);
   }
-  if (c.pixels_shm_id != 0) {
-    GLenum error = LOCAL_PEEK_GL_ERROR("glReadPixels");
-    if (error == GL_NO_ERROR) {
-      if (result != NULL) {
-        *result = true;
-      }
-      FinishReadPixels(c, 0);
-    }
+  GLenum error = LOCAL_PEEK_GL_ERROR("glReadPixels");
+  if (error == GL_NO_ERROR) {
+    if (result != NULL) {
+      *result = true;
+    }
+    FinishReadPixels(c, 0);
   }
 
   return error::kNoError;