Return the actual block capacity from GrBufferAllocPool::makeSpaceAtLeast

It looks like this was changed to return the fallback size instead of
the block capacity for the sake of GrTextureOp, but GrTextureOp does
not call makeSpaceAtLeast() anymore.

For ops that write their vertex data in chunks, it's best to know the
full capacity of the block. This way they can maximize the amount of
data written out per chunk.

Bug: skia:10419
Change-Id: I7d3f74cdfc7d9b89f9d331e09069f8d178c07d81
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/300396
Reviewed-by: Brian Salomon <[email protected]>
Commit-Queue: Chris Dalton <[email protected]>

Author: csmartdalton86

src/gpu/GrBufferAllocPool.cpp

@@ -261,15 +261,8 @@ void* GrBufferAllocPool::makeSpaceAtLeast(size_t minSize,
             back.fBytesFree -= pad;
             fBytesInUse += pad;
 
-            // Give caller all remaining space in this block up to fallbackSize (but aligned
-            // correctly)
-            size_t size;
-            if (back.fBytesFree >= fallbackSize) {
-                SkASSERT(align_down(fallbackSize, alignment) == fallbackSize);
-                size = fallbackSize;
-            } else {
-                size = align_down(back.fBytesFree, alignment);
-            }
+            // Give caller all remaining space in this block (but aligned correctly)
+            size_t size = align_down(back.fBytesFree, alignment);
             *offset = usedBytes;
             *buffer = back.fBuffer;
             *actualSize = size;