Make some CFX_AggDeviceDriver methods private.

In CFX_AggDeviceDriver:
- RenderRasterizer() and SetClipMask() should be private, as they have
  no external callers.
- GetBuffer() only has one caller. Remove it and update its caller.

Also do more forward declarations in fx_agg_driver.h, so almost all
third_party/agg23 includes are contained within fx_agg_driver.cpp. The
exception being core/fxge/win32/fx_win32_device.cpp, which now has to do
IWYU.

Change-Id: Ibc49880878aba0c26d3e1a564acdb02a279a6745
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/74394
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Hui Yingst <nigi@chromium.org>

core/fxge/agg/fx_agg_driver.cpp

diff --git a/core/fxge/agg/fx_agg_driver.cpp b/core/fxge/agg/fx_agg_driver.cpp
index 0100ea1..7e586cb 100644
--- a/core/fxge/agg/fx_agg_driver.cpp
+++ b/core/fxge/agg/fx_agg_driver.cpp
@@ -1103,10 +1103,6 @@
   DestroyPlatform();
 }
 
-uint8_t* CFX_AggDeviceDriver::GetBuffer() const {
-  return m_pBitmap->GetBuffer();
-}
-
 #if !defined(OS_APPLE)
 void CFX_AggDeviceDriver::InitPlatform() {}
 
@@ -1291,7 +1287,7 @@
   if (blend_type != BlendMode::kNormal)
     return false;
 
-  if (!GetBuffer())
+  if (!m_pBitmap->GetBuffer())
     return true;
 
   m_FillOptions = fill_options;

core/fxge/agg/fx_agg_driver.h

diff --git a/core/fxge/agg/fx_agg_driver.h b/core/fxge/agg/fx_agg_driver.h
index 3457478..f5a2727 100644
--- a/core/fxge/agg/fx_agg_driver.h
+++ b/core/fxge/agg/fx_agg_driver.h
@@ -13,7 +13,6 @@
 #include "build/build_config.h"
 #include "core/fxge/cfx_fillrenderoptions.h"
 #include "core/fxge/renderdevicedriver_iface.h"
-#include "third_party/agg23/agg_rasterizer_scanline_aa.h"
 
 class CFX_ClipRgn;
 class CFX_GraphStateData;
@@ -22,6 +21,10 @@
 
 namespace pdfium {
 
+namespace agg {
+class rasterizer_scanline_aa;
+}  // namespace agg
+
 class CFX_AggDeviceDriver final : public RenderDeviceDriverIface {
  public:
   CFX_AggDeviceDriver(const RetainPtr<CFX_DIBitmap>& pBitmap,
@@ -92,6 +95,7 @@
                       const CFX_TextRenderOptions& options) override;
   int GetDriverType() const override;
 
+ private:
   bool RenderRasterizer(pdfium::agg::rasterizer_scanline_aa& rasterizer,
                         uint32_t color,
                         bool bFullCover,
@@ -99,9 +103,6 @@
 
   void SetClipMask(pdfium::agg::rasterizer_scanline_aa& rasterizer);
 
-  virtual uint8_t* GetBuffer() const;
-
- private:
   RetainPtr<CFX_DIBitmap> const m_pBitmap;
   std::unique_ptr<CFX_ClipRgn> m_pClipRgn;
   std::vector<std::unique_ptr<CFX_ClipRgn>> m_StateStack;

core/fxge/win32/DEPS

diff --git a/core/fxge/win32/DEPS b/core/fxge/win32/DEPS
new file mode 100644
index 0000000..5d1d2b3
--- /dev/null
+++ b/core/fxge/win32/DEPS
@@ -0,0 +1,5 @@
+specific_include_rules = {
+  'fx_win32_device.cpp': [
+    '+third_party/agg23/agg_clip_liang_barsky.h',
+  ]
+}

core/fxge/win32/fx_win32_device.cpp

diff --git a/core/fxge/win32/fx_win32_device.cpp b/core/fxge/win32/fx_win32_device.cpp
index e362832..7686506 100644
--- a/core/fxge/win32/fx_win32_device.cpp
+++ b/core/fxge/win32/fx_win32_device.cpp
@@ -34,6 +34,7 @@
 
 #if !defined(_SKIA_SUPPORT_)
 #include "core/fxge/agg/fx_agg_driver.h"
+#include "third_party/agg23/agg_clip_liang_barsky.h"
 #endif
 
 namespace {