[Courgette] Refactor: Add and use Instruction*Receptor classes; call ParseFile() in 2 passes.

courgette/disassembler_elf_32_arm.h

Index: courgette/disassembler_elf_32_arm.h
diff --git a/courgette/disassembler_elf_32_arm.h b/courgette/disassembler_elf_32_arm.h
index 24b8aa83c7002b642ddb543ff0cb6c81b31b1a34..21b6001354982e93c9831b661132f816404a7849 100644
--- a/courgette/disassembler_elf_32_arm.h
+++ b/courgette/disassembler_elf_32_arm.h
@@ -17,6 +17,7 @@
 namespace courgette {
 
 class AssemblyProgram;
+class InstructionReceptor;
 
 enum ARM_RVA {
   ARM_OFF8,
@@ -40,8 +41,8 @@ class DisassemblerElf32ARM : public DisassemblerElf32 {
 
     // TypedRVA interfaces.
     CheckBool ComputeRelativeTarget(const uint8_t* op_pointer) override;
-    CheckBool EmitInstruction(AssemblyProgram* program,
-                              Label* label) override;
+    CheckBool EmitInstruction(Label* label,
+                              InstructionReceptor* receptor) override;
     uint16_t op_size() const override;
 
     uint16_t c_op() const { return c_op_; }
@@ -86,8 +87,8 @@ class DisassemblerElf32ARM : public DisassemblerElf32 {
   CheckBool RelToRVA(Elf32_Rel rel,
                      RVA* result) const override WARN_UNUSED_RESULT;
   CheckBool ParseRelocationSection(const Elf32_Shdr* section_header,
-                                   AssemblyProgram* program)
-      override WARN_UNUSED_RESULT;
+                                   InstructionReceptor* receptor) const override
+      WARN_UNUSED_RESULT;
   CheckBool ParseRel32RelocsFromSection(const Elf32_Shdr* section)
       override WARN_UNUSED_RESULT;