Some fixes for Flutter memory issues.

Now that we're using GrBuffers for uploads, we need to match the size
of the upload buffer a little better to avoid wasting memory, so this
switches to a using either a power-of-two size, or the midpoint between
two powers-of-two.

Also, the mechanism of adding the staging buffers to the current
command buffer was not being invoked when calling submit for a cross-
context texture. Switching to submitToGpu() should handle this.

Change-Id: I8e0e5ae7e4dd00b5969d5e5554e3a2bff5758e81
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/310339
Commit-Queue: Jim Van Verth <jvanverth@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>

src/gpu/GrResourceProvider.cpp

@@ -464,9 +464,13 @@ sk_sp<GrGpuBuffer> GrResourceProvider::createBuffer(size_t size, GrGpuBufferType
     if (kDynamic_GrAccessPattern != accessPattern) {
         return this->gpu()->createBuffer(size, intendedType, accessPattern, data);
     }
-    // bin by pow2 with a reasonable min
+    // bin by pow2+midpoint with a reasonable min
     static const size_t MIN_SIZE = 1 << 12;
-    size_t allocSize = std::max(MIN_SIZE, GrNextSizePow2(size));
+    size_t allocSize = std::max(size, MIN_SIZE);
+    size_t ceilPow2 = GrNextSizePow2(allocSize);
+    size_t floorPow2 = ceilPow2 >> 1;
+    size_t mid = floorPow2 + (floorPow2 >> 1);
+    allocSize = (allocSize <= mid) ? mid : ceilPow2;
 
     GrScratchKey key;
     GrGpuBuffer::ComputeScratchKeyForDynamicVBO(allocSize, intendedType, &key);

src/gpu/mtl/GrMtlGpu.mm

@@ -278,7 +278,7 @@ bool GrMtlGpu::onSubmitToGpu(bool syncCpu) {
 }
 
 std::unique_ptr<GrSemaphore> GrMtlGpu::prepareTextureForCrossContextUsage(GrTexture*) {
-    submitCommandBuffer(SyncQueue::kSkip_SyncQueue);
+    this->submitToGpu(false);
     return nullptr;
 }
 

src/gpu/vk/GrVkGpu.cpp

@@ -2647,7 +2647,7 @@ std::unique_ptr<GrSemaphore> GrVkGpu::prepareTextureForCrossContextUsage(GrTextu
     // TODO: should we have a way to notify the caller that this has failed? Currently if the submit
     // fails (caused by DEVICE_LOST) this will just cause us to fail the next use of the gpu.
     // Eventually we will abandon the whole GPU if this fails.
-    this->submitCommandBuffer(kSkip_SyncQueue);
+    this->submitToGpu(false);
 
     // The image layout change serves as a barrier, so no semaphore is needed.
     // If we ever decide we need to return a semaphore here, we need to make sure GrVkSemaphore is