Revert "Add storage on the surface for its last render task"

This reverts commit ca5b36c474476c20805fd643a1abd1081b469be5.

Reason for revert: This may be blocking the Chrome roll

Original change's description:
> Add storage on the surface for its last render task
> 
> Let's land this and see if it gets us back to baseline on the
> lastRenderTask regression from the bug. If it doesn't, we'll revert it
> since the extra complexity won't have been worth it.
> 
> Bug: skia:10372
> Change-Id: I9d5ae93435b833d575afdc7f219dc8e7c453c92b
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/297836
> Reviewed-by: Robert Phillips <robertphillips@google.com>
> Commit-Queue: Adlai Holler <adlai@google.com>

TBR=robertphillips@google.com,adlai@google.com

Change-Id: Id418d042d1123d946cd99b7b1ba438211cb628ec
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:10372
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/299763
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
diff --git a/src/gpu/GrHashMapWithCache.h b/src/gpu/GrHashMapWithCache.h
new file mode 100644
index 0000000..8a24ecc
--- /dev/null
+++ b/src/gpu/GrHashMapWithCache.h
@@ -0,0 +1,84 @@
+/*
+ * Copyright 2020 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrHashMapWithCache_DEFINED
+#define GrHashMapWithCache_DEFINED
+
+#include "include/private/SkChecksum.h"
+#include "include/private/SkNoncopyable.h"
+#include "include/private/SkTHash.h"
+
+// Cheaper than SkGoodHash and good enough for UniqueID tables.
+struct GrCheapHash {
+    uint32_t operator()(uint32_t val) {
+        return SkChecksum::CheapMix(val);
+    }
+};
+
+/** A hash map that caches the most recently accessed entry.
+    The API is a subset of SkHashMap, and you must provide a
+    sentinel key that will never be present, such as SK_InvalidUniqueID.
+
+    KeyTraits must have:
+      - static K GetInvalidKey()
+*/
+template <typename K, typename V, typename KeyTraits, typename HashT = SkGoodHash>
+class GrHashMapWithCache : public SkNoncopyable {
+public:
+    // How many key/value pairs are in the table?
+    int count() const { return fMap.count(); }
+
+    // Approximately how many bytes of memory do we use beyond sizeof(*this)?
+    size_t approxBytesUsed() const { return fMap.approxBytesUsed(); }
+
+    // N.B. The pointers returned by set() and find() are valid only until the next call to set().
+
+    // If there is key/value entry in the table with this key, return a pointer to the value.
+    // If not, return null.
+    const V* find(const K& key) const {
+        if (key != fLastKey) {
+            fLastKey = key;
+            fLastValue = fMap.find(key);
+        }
+        return fLastValue;
+    }
+
+    // Set key to val in the map, replacing any previous value with the same key.
+    // We copy both key and val, and return a pointer to the value copy now in the map.
+    const V* set(K key, V val) {
+        if (fLastValue && key == fLastKey) {
+            *fLastValue = std::move(val);
+        } else {
+            fLastKey = key;
+            fLastValue = fMap.set(std::move(key), std::move(val));
+        }
+        return fLastValue;
+    }
+
+    // Remove the key/value entry in the table with this key.
+    void remove(K key) {
+        // Match SkTHashMap requirement. The caller can find() if they're unsure.
+        SkASSERT(fMap.find(fLastKey));
+        fLastKey = std::move(key);
+        fLastValue = nullptr;
+        fMap.remove(fLastKey);
+    }
+
+    // Clear the map.
+    void reset() {
+        fLastKey = KeyTraits::GetInvalidKey();
+        fLastValue = nullptr;
+        fMap.reset();
+    }
+
+private:
+    SkTHashMap<K, V, HashT> fMap;
+    mutable K               fLastKey   = KeyTraits::GetInvalidKey();
+    mutable V*              fLastValue = nullptr;
+};
+
+#endif