Support more configurability in GN toolchains

tools/gn/ninja_binary_target_writer.h

Index: tools/gn/ninja_binary_target_writer.h
diff --git a/tools/gn/ninja_binary_target_writer.h b/tools/gn/ninja_binary_target_writer.h
index 14762534ed0f83772acd6ec10f06cf44d7980991..e3236ce52f6f65a896e845a8a3646127dcb5d7ce 100644
--- a/tools/gn/ninja_binary_target_writer.h
+++ b/tools/gn/ninja_binary_target_writer.h
@@ -6,17 +6,18 @@
 #define TOOLS_GN_NINJA_BINARY_TARGET_WRITER_H_
 
 #include "base/compiler_specific.h"
+#include "tools/gn/config_values.h"
 #include "tools/gn/ninja_target_writer.h"
 #include "tools/gn/toolchain.h"
 #include "tools/gn/unique_vector.h"
 
+struct EscapeOptions;
+
 // Writes a .ninja file for a binary target type (an executable, a shared
 // library, or a static library).
 class NinjaBinaryTargetWriter : public NinjaTargetWriter {
  public:
-  NinjaBinaryTargetWriter(const Target* target,
-                          const Toolchain* toolchain,
-                          std::ostream& out);
+  NinjaBinaryTargetWriter(const Target* target, std::ostream& out);
   virtual ~NinjaBinaryTargetWriter();
 
   virtual void Run() OVERRIDE;
@@ -27,14 +28,10 @@ class NinjaBinaryTargetWriter : public NinjaTargetWriter {
   void WriteCompilerVars();
   void WriteSources(std::vector<OutputFile>* object_files);
   void WriteLinkerStuff(const std::vector<OutputFile>& object_files);
-  void WriteLinkerFlags(const Toolchain::Tool& tool,
-                        const OutputFile& windows_manifest);
-  void WriteLibs(const Toolchain::Tool& tool);
-
-  // Writes the build line for linking the target. Includes newline.
-  void WriteLinkCommand(const OutputFile& external_output_file,
-                        const OutputFile& internal_output_file,
-                        const std::vector<OutputFile>& object_files);
+  void WriteLinkerFlags();
+  void WriteLibs();
+  void WriteOutputExtension();
+  void WriteSolibs(const std::vector<OutputFile>& solibs);
 
   // Writes the stamp line for a source set. These are not linked.
   void WriteSourceSetStamp(const std::vector<OutputFile>& object_files);
@@ -57,12 +54,29 @@ class NinjaBinaryTargetWriter : public NinjaTargetWriter {
   // Writes the implicit dependencies for the link or stamp line. This is
   // the "||" and everything following it on the ninja line.
   //
-  // The implicit dependencies are the non-linkable deps passed in as an
+  // The order-only dependencies are the non-linkable deps passed in as an
   // argument, plus the data file depdencies in the target.
-  void WriteImplicitDependencies(
+  void WriteOrderOnlyDependencies(
       const UniqueVector<const Target*>& non_linkable_deps);
 
-  Toolchain::ToolType tool_type_;
+  // Computes the set of output files resulting from compiling the given source
+  // file. If the file can be compiled and the tool exists, fills the outputs in
+  // and writes the tool type to computed_tool_type. If the file is not
+  // compilable, returns false.
+  //
+  // The target that the source belongs to is passed as an argument. In the
+  // case of linking to source sets, this can be different than the target
+  // this class is currently writing.
+  //
+  // The function can succeed with a "NONE" tool type for object files which are
+  // just passed to the output. The output will always be overwritten, not
+  // appended to.
+  bool GetOutputFilesForSource(const Target* target,
+                               const SourceFile& source,
+                               Toolchain::ToolType* computed_tool_type,
+                               std::vector<OutputFile>* outputs) const;
+
+  const Tool* tool_;
 
   DISALLOW_COPY_AND_ASSIGN(NinjaBinaryTargetWriter);
 };