Courgette: Add static method QuickDetect() to optimize program detection.

courgette/disassembler_win32_x86.h

Index: courgette/disassembler_win32_x86.h
diff --git a/courgette/disassembler_win32_x86.h b/courgette/disassembler_win32_x86.h
index 6602f37ea957c33a6d538f0fb18d676948908570..f240980489fb4a16523a84ca87a1758137dfbc35 100644
--- a/courgette/disassembler_win32_x86.h
+++ b/courgette/disassembler_win32_x86.h
@@ -19,7 +19,13 @@ class AssemblyProgram;
 
 class DisassemblerWin32X86 : public DisassemblerWin32 {
  public:
-  DisassemblerWin32X86(const void* start, size_t length);
+  // Returns 'true' if an valid executable is detected using only quick checks.

[huangs, 2016/06/17 15:21:57]

NIT: true does not need ''
NIT: *a* valid executable.

+  static bool QuickDetect(const uint8_t* start, size_t length) {
+    return DisassemblerWin32::QuickDetect(start, length,
+                                          kImageNtOptionalHdr32Magic);
+  }
+
+  DisassemblerWin32X86(const uint8_t* start, size_t length);
   ~DisassemblerWin32X86() override = default;
 
   // Disassembler interfaces.