return Coeff for kPlus_Mode and kMultiply_Mode
now these work correctly on the gpu



git-svn-id: http://skia.googlecode.com/svn/trunk@1116 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/core/SkXfermode.cpp b/src/core/SkXfermode.cpp
index 71482c1..9d54bf6 100644
--- a/src/core/SkXfermode.cpp
+++ b/src/core/SkXfermode.cpp
@@ -448,8 +448,8 @@
     { dstatop_modeproc, SkXfermode::kIDA_Coeff,     SkXfermode::kSA_Coeff },
     { xor_modeproc,     SkXfermode::kIDA_Coeff,     SkXfermode::kISA_Coeff },
 
-    { plus_modeproc,        CANNOT_USE_COEFF,       CANNOT_USE_COEFF },
-    { multiply_modeproc,    CANNOT_USE_COEFF,       CANNOT_USE_COEFF },
+    { plus_modeproc,    SkXfermode::kOne_Coeff,     SkXfermode::kOne_Coeff },
+    { multiply_modeproc,SkXfermode::kZero_Coeff,    SkXfermode::kSC_Coeff },
     { screen_modeproc,      CANNOT_USE_COEFF,       CANNOT_USE_COEFF },
     { overlay_modeproc,     CANNOT_USE_COEFF,       CANNOT_USE_COEFF },
     { darken_modeproc,      CANNOT_USE_COEFF,       CANNOT_USE_COEFF },