Small repro for function-templates-original.cc:

namespace rename_missed_in_export_template_declaration {

template <typename PrimitiveType>
void drawPlatformFocusRing(const PrimitiveType&);

template <typename PrimitiveType>
void drawPlatformFocusRing(const PrimitiveType& primitive) {}

class SkPath;
template void drawPlatformFocusRing<SkPath>(const SkPath&);

}  // namespace rename_missed_in_export_template_declaration

Also - these 2 last declarations are important because of the PLATFORM_EXPORT part.  After deleting the last 2 declarations we would get the following linker error in component build (+ a few more similar errors):

obj/third_party/WebKit/Source/platform/platform/GraphicsContext.o:../../third_party/WebKit/Source/platform/graphics/GraphicsContext.cpp:function blink::GraphicsContext::drawFocusRing(WTF::Vector<blink::IntRect, 0ul, WTF::PartitionAllocator> const&, int, int, blink::Color const&): error: undefined reference to 'void blink::drawPlatformFocusRing<SkPath>(SkPath const&, SkCanvas*, unsigned int, int)'

Smaller test:

template <typename PrimitiveType>
void DrawPlatformFocusRing(const PrimitiveType& primitive) {}

template void DrawPlatformFocusRing<int>(const int&);

AST for the smaller test:

`-FunctionTemplateDecl 0x5be9868 </usr/local/google/home/lukasza/src/chromium4/src/tools/clang/rewrite_to_chrome_style/tests/function-templates-actual.cc:1:1, line:2:61> col:6 drawPlatformFocusRing
  |-TemplateTypeParmDecl 0x5be95a0 <line:1:11, col:20> col:20 referenced typename PrimitiveType
  |-FunctionDecl 0x5be97c0 <line:2:1, col:61> col:6 drawPlatformFocusRing 'void (const PrimitiveType &)'
  | |-ParmVarDecl 0x5be96b8 <col:28, col:49> col:49 primitive 'const PrimitiveType &'
  | `-CompoundStmt 0x5be9900 <col:60, col:61>
  `-FunctionDecl 0x5be9cb0 <col:1, col:61> col:6 drawPlatformFocusRing 'void (const int &)'
    |-TemplateArgument type 'int'
    |-ParmVarDecl 0x5be9c28 <col:28, col:49> col:49 primitive 'const int &'
    `-CompoundStmt 0x5be9900 <col:60, col:61>

It seems that both FunctionDecl-s above point at the same line in the input.  I'd have to double-check this, but this seems wrong and seems to be similar to (but not quite the same as) https://llvm.org/bugs/show_bug.cgi?id=29145 trouble we had with unnamed parameters.

I've opened https://llvm.org/bugs/show_bug.cgi?id=30338

 Issue 685357  has been merged into this issue.

 Issue 685695  has been merged into this issue.

This can be fixed manually (via the manual fixes stashes in https://crrev.com/2329463004).