Revert "Remove CFX_FixedBufGrow"

This reverts commit 55d1d0191ea8316df32858d8cc62fb7c620e8613.

Reason for revert: Slowing down corpus tests by a lot on Mac/Win

Original change's description:
> Remove CFX_FixedBufGrow
> 
> This Cl replaces the CFX_FixedBufGrow class with std::vector.
> 
> Change-Id: I85c85b7a8de4794840b561e09841bb464cfa9dfe
> Reviewed-on: https://pdfium-review.googlesource.com/3138
> Reviewed-by: Tom Sepez <tsepez@chromium.org>
> Commit-Queue: dsinclair <dsinclair@chromium.org>
> 

TBR=tsepez@chromium.org,dsinclair@chromium.org,pdfium-reviews@googlegroups.com
# Not skipping CQ checks because original CL landed > 1 day ago.

Change-Id: Iaee27570f140b2033b5d8fb8f3077fc839558d64
Reviewed-on: https://pdfium-review.googlesource.com/3158
Reviewed-by: Nicolás Peña <npm@chromium.org>
Commit-Queue: Nicolás Peña <npm@chromium.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/core/fxcrt/fx_basic.h b/core/fxcrt/fx_basic.h
index 2786918fd1..076766a0a2 100644
--- a/core/fxcrt/fx_basic.h
+++ b/core/fxcrt/fx_basic.h
@@ -317,6 +317,23 @@ class CFX_ArrayTemplate : public CFX_BasicArray {
   }
 };
 
+template <class DataType, int FixedSize>
+class CFX_FixedBufGrow {
+ public:
+  explicit CFX_FixedBufGrow(int data_size) {
+    if (data_size > FixedSize) {
+      m_pGrowData.reset(FX_Alloc(DataType, data_size));
+      return;
+    }
+    FXSYS_memset(m_FixedData, 0, sizeof(DataType) * FixedSize);
+  }
+  operator DataType*() { return m_pGrowData ? m_pGrowData.get() : m_FixedData; }
+
+ private:
+  DataType m_FixedData[FixedSize];
+  std::unique_ptr<DataType, FxFreeDeleter> m_pGrowData;
+};
+
 class CFX_BitStream {
  public:
   void Init(const uint8_t* pData, uint32_t dwSize);