Vulkan: Remove Host->device availability barrier.

src/libANGLE/renderer/vulkan/BufferVk.cpp

@@ -372,7 +372,6 @@ angle::Result BufferVk::unmapImpl(ContextVk *contextVk)
     if (!mShadowBuffer.valid())
     {
         mBuffer->unmap(contextVk->getRenderer());
-        mBuffer->onExternalWrite(VK_ACCESS_HOST_WRITE_BIT);
     }
     else
     {
@@ -483,7 +482,6 @@ angle::Result BufferVk::directUpdate(ContextVk *contextVk,
     memcpy(mapPointer, data, size);
     mBuffer->unmap(contextVk->getRenderer());
     ASSERT(mBuffer->isCoherent());
-    mBuffer->onExternalWrite(VK_ACCESS_HOST_WRITE_BIT);
 
     return angle::Result::Continue;
 }
@@ -505,7 +503,6 @@ angle::Result BufferVk::stagedUpdate(ContextVk *contextVk,
     memcpy(mapPointer, data, size);
     ASSERT(!stagingBuffer->isCoherent());
     ANGLE_TRY(stagingBuffer->flush(contextVk));
-    stagingBuffer->getCurrentBuffer()->onExternalWrite(VK_ACCESS_HOST_WRITE_BIT);
 
     // Enqueue a copy command on the GPU.
     VkBufferCopy copyRegion = {stagingBufferOffset, offset, size};

src/libANGLE/renderer/vulkan/OverlayVk.cpp

@@ -105,8 +105,6 @@ angle::Result OverlayVk::createFont(ContextVk *contextVk)
     ANGLE_TRY(fontDataBuffer.get().flush(renderer, 0, fontDataBuffer.get().getSize()));
     fontDataBuffer.get().unmap(renderer);
 
-    fontDataBuffer.get().onExternalWrite(VK_ACCESS_HOST_WRITE_BIT);
-
     // Create the font image.
     ANGLE_TRY(
         mFontImage.init(contextVk, gl::TextureType::_2D,
@@ -172,8 +170,6 @@ angle::Result OverlayVk::cullWidgets(ContextVk *contextVk)
     ANGLE_TRY(enabledWidgetsBuffer.get().flush(renderer, 0, enabledWidgetsBuffer.get().getSize()));
     enabledWidgetsBuffer.get().unmap(renderer);
 
-    enabledWidgetsBuffer.get().onExternalWrite(VK_ACCESS_HOST_WRITE_BIT);
-
     // Allocate mCulledWidget and its view.
     VkExtent3D culledWidgetsExtent = {
         UnsignedCeilDivide(mPresentImageExtent.width, mSubgroupSize[0]),

src/libANGLE/renderer/vulkan/vk_helpers.h

@@ -751,15 +751,6 @@ class BufferHelper final : public Resource
 
     bool isMapped() const { return mMappedMemory != nullptr; }
 
-    // Set write access mask when the buffer is modified externally, e.g. by host.  There is no
-    // graph resource to create a dependency to.
-    void onExternalWrite(VkAccessFlags writeAccessType)
-    {
-        ASSERT(writeAccessType == VK_ACCESS_HOST_WRITE_BIT);
-        mCurrentWriteAccess |= writeAccessType;
-        mCurrentWriteStages |= VK_PIPELINE_STAGE_HOST_BIT;
-    }
-
     // Also implicitly sets up the correct barriers.
     angle::Result copyFromBuffer(ContextVk *contextVk,
                                  BufferHelper *srcBuffer,