FileVersionInfoWin: BASE_EXPORT the class instead of select methods.

Some methods are being called from a different component, so should be
exported. Rather than selectively exporting them, we just made the
entire class (and its parent class, FileVersionInfo) BASE_EXPORTed.

Note: This is not currently breaking the build, because the methods are
called by virtual dispatch, but in principle, they should be exported.
Context: I am investigating adding the "final" keyword to a bunch of
classes (http://crbug.com/482800) and this breaks once "final" is added
to FileVersionInfoWin.

BUG=484939

Review URL: https://codereview.chromium.org/1122413002

Cr-Commit-Position: refs/heads/master@{#328683}

diff --git a/base/file_version_info_win.h b/base/file_version_info_win.h
index 92d0844a..09d8d37 100644
--- a/base/file_version_info_win.h
+++ b/base/file_version_info_win.h

@@ -15,10 +15,10 @@
 struct tagVS_FIXEDFILEINFO;
 typedef tagVS_FIXEDFILEINFO VS_FIXEDFILEINFO;
 
-class FileVersionInfoWin : public FileVersionInfo {
+class BASE_EXPORT FileVersionInfoWin : public FileVersionInfo {
  public:
-  BASE_EXPORT FileVersionInfoWin(void* data, WORD language, WORD code_page);
-  BASE_EXPORT ~FileVersionInfoWin() override;
+  FileVersionInfoWin(void* data, WORD language, WORD code_page);
+  ~FileVersionInfoWin() override;
 
   // Accessors to the different version properties.
   // Returns an empty string if the property is not found.
@@ -40,11 +40,11 @@
   bool is_official_build() override;
 
   // Lets you access other properties not covered above.
-  BASE_EXPORT bool GetValue(const wchar_t* name, std::wstring* value);
+  bool GetValue(const wchar_t* name, std::wstring* value);
 
   // Similar to GetValue but returns a wstring (empty string if the property
   // does not exist).
-  BASE_EXPORT std::wstring GetStringValue(const wchar_t* name);
+  std::wstring GetStringValue(const wchar_t* name);
 
   // Get the fixed file info if it exists. Otherwise NULL
   VS_FIXEDFILEINFO* fixed_file_info() { return fixed_file_info_; }